A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.
Drugs that bind to and activate cholinergic receptors.
One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.
Drugs that bind to and activate muscarinic cholinergic receptors (RECEPTORS, MUSCARINIC). Muscarinic agonists are most commonly used when it is desirable to increase smooth muscle tone, especially in the GI tract, urinary bladder and the eye. They may also be used to reduce heart rate.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Drugs that mimic the effects of parasympathetic nervous system activity. Included here are drugs that directly stimulate muscarinic receptors and drugs that potentiate cholinergic activity, usually by slowing the breakdown of acetylcholine (CHOLINESTERASE INHIBITORS). Drugs that stimulate both sympathetic and parasympathetic postganglionic neurons (GANGLIONIC STIMULANTS) are not included here.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.
A subclass of muscarinic receptor that mediates cholinergic-induced contraction in a variety of SMOOTH MUSCLES.
A high-affinity muscarinic antagonist commonly used as a tool in animal and tissue studies.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
A specific subtype of muscarinic receptor found in the lower BRAIN, the HEART and in SMOOTH MUSCLE-containing organs. Although present in smooth muscle the M2 muscarinic receptor appears not to be involved in contractile responses.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
An antimuscarinic agent that inhibits gastric secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular, and urinary function. It promotes the healing of duodenal ulcers and due to its cytoprotective action is beneficial in the prevention of duodenal ulcer recurrence. It also potentiates the effect of other antiulcer agents such as CIMETIDINE and RANITIDINE. It is generally well tolerated by patients.
A muscarinic antagonist used to study binding characteristics of muscarinic cholinergic receptors.
The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.
Agents that inhibit the actions of the parasympathetic nervous system. The major group of drugs used therapeutically for this purpose is the MUSCARINIC ANTAGONISTS.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
The largest of the three pairs of SALIVARY GLANDS. They lie on the sides of the FACE immediately below and in front of the EAR.
Any drug used for its actions on cholinergic systems. Included here are agonists and antagonists, drugs that affect the life cycle of ACETYLCHOLINE, and drugs that affect the survival of cholinergic neurons. The term cholinergic agents is sometimes still used in the narrower sense of MUSCARINIC AGONISTS, although most modern texts discourage that usage.
A specific subtype of muscarinic receptor that has a high affinity for the drug PIRENZEPINE. It is found in the peripheral GANGLIA where it signals a variety of physiological functions such as GASTRIC ACID secretion and BRONCHOCONSTRICTION. This subtype of muscarinic receptor is also found in neuronal tissues including the CEREBRAL CORTEX and HIPPOCAMPUS where it mediates the process of MEMORY and LEARNING.
Phosphoric acid esters of inositol. They include mono- and polyphosphoric acid esters, with the exception of inositol hexaphosphate which is PHYTIC ACID.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to the hexahydroxy alcohol, myo-inositol. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid, myo-inositol, and 2 moles of fatty acids.
The relationship between the dose of an administered drug and the response of the organism to the drug.
Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology.
A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.
A non-hydrolyzed muscarinic agonist used as a research tool.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Organic chemicals which have two amino groups in an aliphatic chain.
An octapeptide hormone present in the intestine and brain. When secreted from the gastric mucosa, it stimulates the release of bile from the gallbladder and digestive enzymes from the pancreas.
Rounded or pyramidal cells of the GASTRIC GLANDS. They secrete HYDROCHLORIC ACID and produce gastric intrinsic factor, a glycoprotein that binds VITAMIN B12.
Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.
That phase of a muscle twitch during which a muscle returns to a resting position.
The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.
Compounds containing the hexamethylenebis(trimethylammonium) cation. Members of this group frequently act as antihypertensive agents and selective ganglionic blocking agents.
The tear-forming and tear-conducting system which includes the lacrimal glands, eyelid margins, conjunctival sac, and the tear drainage system.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
Simple sweat glands that secrete sweat directly onto the SKIN.
A cholinesterase inhibitor that is rapidly absorbed through membranes. It can be applied topically to the conjunctiva. It also can cross the blood-brain barrier and is used when central nervous system effects are desired, as in the treatment of severe anticholinergic toxicity.
A pyrazolone with analgesic, anti-inflammatory, and antipyretic properties but has risk of AGRANULOCYTOSIS. A breath test with 13C-labeled aminopyrine has been used as a non-invasive measure of CYTOCHROME P-450 metabolic activity in LIVER FUNCTION TESTS.
Drugs that bind to but do not activate CHOLINERGIC RECEPTORS, thereby blocking the actions of ACETYLCHOLINE or cholinergic agonists.
Potent activator of the adenylate cyclase system and the biosynthesis of cyclic AMP. From the plant COLEUS FORSKOHLII. Has antihypertensive, positive inotropic, platelet aggregation inhibitory, and smooth muscle relaxant activities; also lowers intraocular pressure and promotes release of hormones from the pituitary gland.
A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.
Use of electric potential or currents to elicit biological responses.
The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
An analog of benzilylcholine mustard. It is an alkylating nitrogen mustard analog that binds specifically and irreversibly to cholinergic muscarinic receptors and is used as an affinity label to isolate and study the receptors.
Analogs or derivatives of scopolamine.
'Sugar phosphates' are organic compounds that consist of a sugar molecule linked to one or more phosphate groups, playing crucial roles in biochemical processes such as energy transfer and nucleic acid metabolism.
Agents causing contraction of the pupil of the eye. Some sources use the term miotics only for the parasympathomimetics but any drug used to induce miosis is included here.
Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
A slowly hydrolyzed muscarinic agonist with no nicotinic effects. Pilocarpine is used as a miotic and in the treatment of glaucoma.
The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.
An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.
Sweat-producing structures that are embedded in the DERMIS. Each gland consists of a single tube, a coiled body, and a superficial duct.
An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.
One of the virulence factors produced by BORDETELLA PERTUSSIS. It is a multimeric protein composed of five subunits S1 - S5. S1 contains mono ADPribose transferase activity.
A neuromuscular blocker and active ingredient in CURARE; plant based alkaloid of Menispermaceae.
A plant genus of the family APIACEAE. Members contain THAPSIGARGIN and other guaianolides (SESQUITERPENES, GUAIANOLIDE).
Compounds that contain the decamethylenebis(trimethyl)ammonium radical. These compounds frequently act as neuromuscular depolarizing agents.
A set of BACTERIAL ADHESINS and TOXINS, BIOLOGICAL produced by BORDETELLA organisms that determine the pathogenesis of BORDETELLA INFECTIONS, such as WHOOPING COUGH. They include filamentous hemagglutinin; FIMBRIAE PROTEINS; pertactin; PERTUSSIS TOXIN; ADENYLATE CYCLASE TOXIN; dermonecrotic toxin; tracheal cytotoxin; Bordetella LIPOPOLYSACCHARIDES; and tracheal colonization factor.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Drugs that interrupt transmission at the skeletal neuromuscular junction by causing sustained depolarization of the motor end plate. These agents are primarily used as adjuvants in surgical anesthesia to cause skeletal muscle relaxation.
A group of amylolytic enzymes that cleave starch, glycogen, and related alpha-1,4-glucans. (Stedman, 25th ed) EC 3.2.1.-.
A peptide, of about 33 amino acids, secreted by the upper INTESTINAL MUCOSA and also found in the central nervous system. It causes gallbladder contraction, release of pancreatic exocrine (or digestive) enzymes, and affects other gastrointestinal functions. Cholecystokinin may be the mediator of satiety.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
A nicotinic cholinergic antagonist often referred to as the prototypical ganglionic blocker. It is poorly absorbed from the gastrointestinal tract and does not cross the blood-brain barrier. It has been used for a variety of therapeutic purposes including hypertension but, like the other ganglionic blockers, it has been replaced by more specific drugs for most purposes, although it is widely used a research tool.
The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.
Nerve fibers liberating acetylcholine at the synapse after an impulse.
A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.
A sesquiterpene lactone found in roots of THAPSIA. It inhibits CA(2+)-TRANSPORTING ATPASE mediated uptake of CALCIUM into SARCOPLASMIC RETICULUM.
An isomer of glucose that has traditionally been considered to be a B vitamin although it has an uncertain status as a vitamin and a deficiency syndrome has not been identified in man. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1379) Inositol phospholipids are important in signal transduction.
Guanosine 5'-(trihydrogen diphosphate), monoanhydride with phosphorothioic acid. A stable GTP analog which enjoys a variety of physiological actions such as stimulation of guanine nucleotide-binding proteins, phosphoinositide hydrolysis, cyclic AMP accumulation, and activation of specific proto-oncogenes.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.

Modulation of long-term synaptic depression in visual cortex by acetylcholine and norepinephrine. (1/3283)

In a slice preparation of rat visual cortex, we discovered that paired-pulse stimulation (PPS) elicits a form of homosynaptic long-term depression (LTD) in the superficial layers when carbachol (CCh) or norepinephrine (NE) is applied concurrently. PPS by itself, or CCh and NE in the absence of synaptic stimulation, produced no lasting change. The LTD induced by PPS in the presence of NE or CCh is of comparable magnitude with that obtained with prolonged low-frequency stimulation (LFS) but requires far fewer stimulation pulses (40 vs 900). The cholinergic facilitation of LTD was blocked by atropine and pirenzepine, suggesting involvement of M1 receptors. The noradrenergic facilitation of LTD was blocked by urapidil and was mimicked by methoxamine, suggesting involvement of alpha1 receptors. beta receptor agonists and antagonists were without effect. Induction of LTD by PPS was inhibited by NMDA receptor blockers (completely in the case of NE; partially in the case of CCh), suggesting that one action of the modulators is to control the gain of NMDA receptor-dependent homosynaptic LTD in visual cortex. We propose that this is a mechanism by which cholinergic and noradrenergic inputs to the neocortex modulate naturally occurring receptive field plasticity.  (+info)

Metrifonate increases neuronal excitability in CA1 pyramidal neurons from both young and aging rabbit hippocampus. (2/3283)

The effects of metrifonate, a second generation cholinesterase inhibitor, were examined on CA1 pyramidal neurons from hippocampal slices of young and aging rabbits using current-clamp, intracellular recording techniques. Bath perfusion of metrifonate (10-200 microM) dose-dependently decreased both postburst afterhyperpolarization (AHP) and spike frequency adaptation (accommodation) in neurons from young and aging rabbits (AHP: p < 0.002, young; p < 0.050, aging; accommodation: p < 0.024, young; p < 0.001, aging). These reductions were mediated by muscarinic cholinergic transmission, because they were blocked by addition of atropine (1 microM) to the perfusate. The effects of chronic metrifonate treatment (12 mg/kg for 3 weeks) on CA1 neurons of aging rabbits were also examined ex vivo. Neurons from aging rabbits chronically treated with metrifonate had significantly reduced spike frequency accommodation, compared with vehicle-treated rabbits. Chronic metrifonate treatment did not result in a desensitization to metrifonate ex vivo, because bath perfusion of metrifonate (50 microM) significantly decreased the AHP and accommodation in neurons from both chronically metrifonate- and vehicle-treated aging rabbits. We propose that the facilitating effect of chronic metrifonate treatment on acquisition of hippocampus-dependent tasks such as trace eyeblink conditioning by aging subjects may be caused by this increased excitability of CA1 pyramidal neurons.  (+info)

N-type voltage-dependent calcium channels mediate the nicotinic enhancement of GABA release in chick brain. (3/3283)

The role of voltage-dependent calcium channels (VDCCs) in the nicotinic acetylcholine receptor (nAChR)-mediated enhancement of spontaneous GABAergic inhibitory postsynaptic currents (IPSCs) was investigated in chick brain slices. Whole cell recordings of neurons in the lateral spiriform (SpL) and ventral lateral geniculate (LGNv) nuclei showed that cadmium chloride (CdCl2) blocked the carbachol-induced increase of spontaneous GABAergic IPSCs, indicating that VDCCs might be involved. To conclusively show a role for VDCCs, the presynaptic effect of carbachol on SpL and LGNv neurons was examined in the presence of selective blockers of VDCC subtypes. omega-Conotoxin GVIA, a selective antagonist of N-type channels, significantly reduced the nAChR-mediated enhancement of gamma-aminobutyric acid (GABA) release in the SpL by 78% compared with control responses. Nifedipine, an L-type channel blocker, and omega-Agatoxin-TK, a P/Q-type channel blocker, did not inhibit the enhancement of GABAergic IPSCs. In the LGNv, omega-Conotoxin GVIA also significantly reduced the nAChR-mediated enhancement of GABA release by 71% from control values. Although omega-Agatoxin-TK did not block the nicotinic enhancement, L-type channel blockers showed complex effects on the nAChR-mediated enhancement. These results indicate that the nAChR-mediated enhancement of spontaneous GABAergic IPSCs requires activation of N-type channels in both the SpL and LGNv.  (+info)

Influence of nitric oxide modulators on cholinergically stimulated hormone release from mouse islets. (4/3283)

1. We have investigated, with a combined in vitro and in vivo approach, the influence on insulin and glucagon release stimulated by the cholinergic, muscarinic agonist carbachol of different NO modulators, i.e. the nitric oxide synthase (NOS) inhibitors NG-nitro-L-arginine methyl ester (L-NAME), NG-monomethyl-L-arginine (L-NMMA) and 7-nitroindazole as well as the intracellular NO donor hydroxylamine. 2. At basal glucose (7 mM) carbachol dose-dependently stimulated insulin release from isolated islets with a half-maximal response at approximately 1 microM of the agonist. In the presence of 5 mM L-NAME (a concentration that did not influence basal insulin release) the insulin response was markedly increased along the whole dose-response curve and the threshold for carbachol stimulation was significantly lowered. 3. Carbachol-stimulated islets displayed an increased insulin release and a suppressed glucagon release in the presence of L-NAME, L-NMMA or 7-nitroindazole. Significant suppression of glucagon release (except for L-NAME) was achieved at lower concentrations (approximately 0.1-0.5 mM) of the NOS inhibitors than the potentiation of insulin release (1.0-5.0 mM). The intracellular NO donor hydroxylamine dose-dependently inhibited carbachol-induced insulin release but stimulated glucagon release only at a low concentration (3 microM). 4. In islets depolarized with 30 mM K+ in the presence of the KATP channel opener diazoxide, NOS inhibition by 5 mM L-NAME still markedly potentiated carbachol-induced insulin release (although less so than in normal islets) and suppressed glucagon release. 5. In vivo pretreatment of mice with L-NAME was followed by a markedly increased insulin release and a reduced glucagon release in response to an i.v. injection of carbachol. 6. The data suggest that NO is a negative modulator of insulin release but a positive modulator of glucagon release induced by cholinergic muscarinic stimulation. These effects were also evident in K+ depolarized islets and thus NO might exert a major influence on islet hormone secretion independently of membrane depolarization events.  (+info)

Modulation of chloride, potassium and bicarbonate transport by muscarinic receptors in a human adenocarcinoma cell line. (5/3283)

1. Short-circuit current (I(SC)) responses to carbachol (CCh) were investigated in Colony 1 epithelia, a subpopulation of the HCA-7 adenocarcinoma cell line. In Krebs-Henseleit (KH) buffer, CCh responses consisted of three I(SC) components: an unusual rapid decrease (the 10 s spike) followed by an upward spike at 30 s and a slower transient increase (the 2 min peak). This response was not potentiated by forskolin; rather, CCh inhibited cyclic AMP-stimulated I(SC). 2. In HCO3- free buffer, the decrease in forskolin-elevated I(SC) after CCh was reduced, although the interactions between CCh and forskolin remained at best additive rather than synergistic. When Cl- anions were replaced by gluconate, both Ca2+- and cyclic AMP-mediated electrogenic responses were significantly inhibited. 3. Basolateral Ba2+ (1-10 mM) and 293B (10 microM) selectively inhibited forskolin stimulation of I(SC), without altering the effects of CCh. Under Ba2+- or 293B-treated conditions, CCh responses were potentiated by pretreatment with forskolin. 4. Basolateral charybdotoxin (50 nM) significantly increased the size of the 10 s spike of CCh responses in both KH and HCO3- free medium, without affecting the 2 min peak. The enhanced 10 s spike was inhibited by prior addition of 5 mM apical Ba2+. Charybdotoxin did not affect forskolin responses. 5. In epithelial layers prestimulated with forskolin, the muscarinic antagonists atropine and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, both at 100 nM) abolished subsequent 10 microM CCh responses. Following addition of p-fluoro hexahydro-sila-difenidol (pF-HHSiD, 10 microM) or pirenzepine (1 microM), qualitative changes in the CCh response time-profile also indicated a rightward shift of the agonist concentration-response curve; however, 1 microM gallamine had no effect. These results suggest that a single M3-like receptor subtype mediates the secretory response to CCh. 6. It is concluded that CCh and forskolin activate discrete populations of basolateral K+ channels gated by either Ca2+ or cyclic AMP, but that the Cl- permeability of the apical membrane may limit their combined effects on electrogenic Cl- secretion. In addition, CCh activates a Ba2+-sensitive apical K+ conductance leading to electrogenic K+ transport. Both agents may also modulate HCO3- secretion through a mechanism at least partially dependent on carbonic anhydrase.  (+info)

Dose-response slope of forced oscillation and forced expiratory parameters in bronchial challenge testing. (6/3283)

In population studies, the provocative dose (PD) of bronchoconstrictor causing a significant decrement in lung function cannot be calculated for most subjects. Dose-response curves for carbachol were examined to determine whether this relationship can be summarized by means of a continuous index likely to be calculable for all subjects, namely the two-point dose response slope (DRS) of mean resistance (Rm) and resistance at 10 Hz (R10) measured by the forced oscillation technique (FOT). Five doses of carbachol (320 microg each) were inhaled by 71 patients referred for investigation of asthma (n=16), chronic cough (n=15), nasal polyposis (n=8), chronic rhinitis (n=8), dyspnoea (n=8), urticaria (n=5), post-anaphylactic shock (n=4) and miscellaneous conditions (n=7). FOT resistance and forced expiratory volume in one second (FEV1) were measured in close succession. The PD of carbachol leading to a fall in FEV1 > or = 20% (PD20) or a rise in Rm or R10 > or = 47% (PD47,Rm and PD47,R10) were calculated by interpolation. DRS for FEV1 (DRSFEV1), Rm (DRSRm) and R10 (DRSR10) were obtained as the percentage change at last dose divided by the total dose of carbachol. The sensitivity (Se) and specificity (Sp) of DRSRm, DRS10 delta%Rm and delta%R10 in detecting spirometric bronchial hyperresponsiveness (BHR, fall in FEV1 > or = 20%) were assessed by receiver operating characteristic (ROC) curves. There were 23 (32%) "spirometric" reactors. PD20 correlated strongly with DRSFEV1 (r=-0.962; p=0.0001); PD47,Rm correlated significantly with DRSRm (r=-0.648; p=0.0001) and PD47,R10 with DRSR10 (r=-0.552; p=0.0001). DRSFEV1 correlated significantly with both DRSRm (r=0.700; p=0.0001) and DRSR10 (r=0.784; p=0.0001). The Se and Sp of the various FOT indices to correctly detect spirometric BHR were as follows: DRSRm: Se=91.3%, Sp=81.2%; DRSR10: Se=91.3%, Sp=95.8%; delta%Rm: Se=86.9%, Sp=52.1%; and delta%R10: Se=91.3%, Sp=58.3%. Dose-response slopes of indices of forced oscillation technique resistance, especially the dose-response slope of resistance at 10Hz are proposed as simple quantitative indices of bronchial responsiveness which can be calculated for all subjects and that may be useful in occupational epidemiology.  (+info)

Compliance and stability of the bronchial wall in a model of allergen-induced lung inflammation. (7/3283)

Airway wall remodeling in response to inflammation might alter load on airway smooth muscle and/or change airway wall stability. We therefore determined airway wall compliance and closing pressures in an animal model. Weanling pigs were sensitized to ovalbumin (OVA; ip and sc, n = 6) and were subsequently challenged three times with OVA aerosol. Control pigs received 0.9% NaCl (n = 4) in place of OVA aerosol. Bronchoconstriction in vivo was assessed from lung resistance and dynamic compliance. Semistatic airway compliance was recorded ex vivo in isolated segments of bronchus, after the final OVA aerosol or 0.9% NaCl challenge. Internally or externally applied pressure needed to close bronchial segments was determined in the absence or presence of carbachol (1 microM). Sensitized pig lungs exhibited immediate bronchoconstriction to OVA aerosol and also peribronchial accumulations of monocytes and granulocytes. Compliance was reduced in sensitized bronchi in vitro (P < 0.01), and closing pressures were increased (P < 0.05). In the presence of carbachol, closing pressures of control and sensitized bronchi were not different. We conclude that sensitization and/or inflammation increases airway load and airway stability.  (+info)

Selective activation of heterologously expressed G protein-gated K+ channels by M2 muscarinic receptors in rat sympathetic neurones. (8/3283)

1. G protein-regulated inward rectifier K+ (GIRK) channels were over-expressed in dissociated rat superior cervical sympathetic (SCG) neurones by co-transfecting green fluorescent protein (GFP)-, GIRK1- and GIRK2-expressing plasmids using the biolistic technique. Membrane currents were subsequently recorded with whole-cell patch electrodes. 2. Co-transfected cells had larger Ba2+-sensitive inwardly rectifying currents and 13 mV more negative resting potentials (in 3 mM [K+]o) than non-transfected cells, or cells transfected with GIRK1 or GIRK2 alone. 3. Carbachol (CCh, 1-30 microM) increased the inwardly rectifying current in 70 % of GIRK1+ GIRK2-transfected cells by 261 +/- 53 % (n = 6, CCh 30 microM) at -120 mV, but had no effect in non-transfected cells or in cells transfected with GIRK1 or GIRK2 alone. Pertussis toxin prevented the effect of carbachol but had no effect on basal currents. 4. The effect of CCh was antagonized by 6 nM tripitramine but not by 100 nM pirenzepine, consistent with activation of endogenous M2 muscarinic acetylcholine receptors. 5. In contrast, inhibition of the voltage-activated Ca2+ current by CCh was antagonized by 100 nM pirenzepine but not by 6 nM tripitramine, indicating that it was mediated by M4 muscarinic acetylcholine receptors. 6. We conclude that endogenous M2 and M4 muscarinic receptors selectively couple to GIRK currents and Ca2+ currents respectively, with negligible cross-talk.  (+info)

Carbachol is a cholinergic agonist, which means it stimulates the parasympathetic nervous system by mimicking the action of acetylcholine, a neurotransmitter that is involved in transmitting signals between nerves and muscles. Carbachol binds to both muscarinic and nicotinic receptors, but its effects are more pronounced on muscarinic receptors.

Carbachol is used in medical treatments to produce miosis (pupil constriction), lower intraocular pressure, and stimulate gastrointestinal motility. It can also be used as a diagnostic tool to test for certain conditions such as Hirschsprung's disease.

Like any medication, carbachol can have side effects, including sweating, salivation, nausea, vomiting, diarrhea, bradycardia (slow heart rate), and bronchoconstriction (narrowing of the airways in the lungs). It should be used with caution and under the supervision of a healthcare professional.

Cholinergic agonists are substances that bind to and activate cholinergic receptors, which are neuroreceptors that respond to the neurotransmitter acetylcholine. These agents can mimic the effects of acetylcholine in the body and are used in medical treatment to produce effects such as pupil constriction, increased gastrointestinal motility, bronchodilation, and improved cognition. Examples of cholinergic agonists include pilocarpine, bethanechol, and donepezil.

Muscarinic receptors are a type of G protein-coupled receptor (GPCR) that bind to the neurotransmitter acetylcholine. They are found in various organ systems, including the nervous system, cardiovascular system, and respiratory system. Muscarinic receptors are activated by muscarine, a type of alkaloid found in certain mushrooms, and are classified into five subtypes (M1-M5) based on their pharmacological properties and signaling pathways.

Muscarinic receptors play an essential role in regulating various physiological functions, such as heart rate, smooth muscle contraction, glandular secretion, and cognitive processes. Activation of M1, M3, and M5 muscarinic receptors leads to the activation of phospholipase C (PLC) and the production of inositol trisphosphate (IP3) and diacylglycerol (DAG), which increase intracellular calcium levels and activate protein kinase C (PKC). Activation of M2 and M4 muscarinic receptors inhibits adenylyl cyclase, reducing the production of cAMP and modulating ion channel activity.

In summary, muscarinic receptors are a type of GPCR that binds to acetylcholine and regulates various physiological functions in different organ systems. They are classified into five subtypes based on their pharmacological properties and signaling pathways.

Muscarinic agonists are a type of medication that binds to and activates muscarinic acetylcholine receptors, which are found in various organ systems throughout the body. These receptors are activated naturally by the neurotransmitter acetylcholine, and when muscarinic agonists bind to them, they mimic the effects of acetylcholine.

Muscarinic agonists can have a range of effects on different organ systems, depending on which receptors they activate. For example, they may cause bronchodilation (opening up of the airways) in the respiratory system, decreased heart rate and blood pressure in the cardiovascular system, increased glandular secretions in the gastrointestinal and salivary systems, and relaxation of smooth muscle in the urinary and reproductive systems.

Some examples of muscarinic agonists include pilocarpine, which is used to treat dry mouth and glaucoma, and bethanechol, which is used to treat urinary retention. It's important to note that muscarinic agonists can also have side effects, such as sweating, nausea, vomiting, and diarrhea, due to their activation of receptors in various organ systems.

Atropine is an anticholinergic drug that blocks the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. It is derived from the belladonna alkaloids, which are found in plants such as deadly nightshade (Atropa belladonna), Jimson weed (Datura stramonium), and Duboisia spp.

In clinical medicine, atropine is used to reduce secretions, increase heart rate, and dilate the pupils. It is often used before surgery to dry up secretions in the mouth, throat, and lungs, and to reduce salivation during the procedure. Atropine is also used to treat certain types of nerve agent and pesticide poisoning, as well as to manage bradycardia (slow heart rate) and hypotension (low blood pressure) caused by beta-blockers or calcium channel blockers.

Atropine can have several side effects, including dry mouth, blurred vision, dizziness, confusion, and difficulty urinating. In high doses, it can cause delirium, hallucinations, and seizures. Atropine should be used with caution in patients with glaucoma, prostatic hypertrophy, or other conditions that may be exacerbated by its anticholinergic effects.

Parasympathomimetics are substances or drugs that mimic the actions of the parasympathetic nervous system. The parasympathetic nervous system is one of the two branches of the autonomic nervous system, which regulates involuntary physiological functions. It is responsible for the "rest and digest" response, and its neurotransmitter is acetylcholine.

Parasympathomimetic drugs work by either directly stimulating muscarinic receptors or increasing the availability of acetylcholine in the synaptic cleft. These drugs can have various effects on different organs, depending on the specific receptors they target. Some common effects include decreasing heart rate and contractility, reducing respiratory rate, constricting pupils, increasing glandular secretions (such as saliva and sweat), stimulating digestion, and promoting urination and defecation.

Examples of parasympathomimetic drugs include pilocarpine, which is used to treat dry mouth and glaucoma; bethanechol, which is used to treat urinary retention and neurogenic bladder; and neostigmine, which is used to treat myasthenia gravis and reverse the effects of non-depolarizing muscle relaxants.

Smooth muscle, also known as involuntary muscle, is a type of muscle that is controlled by the autonomic nervous system and functions without conscious effort. These muscles are found in the walls of hollow organs such as the stomach, intestines, bladder, and blood vessels, as well as in the eyes, skin, and other areas of the body.

Smooth muscle fibers are shorter and narrower than skeletal muscle fibers and do not have striations or sarcomeres, which give skeletal muscle its striped appearance. Smooth muscle is controlled by the autonomic nervous system through the release of neurotransmitters such as acetylcholine and norepinephrine, which bind to receptors on the smooth muscle cells and cause them to contract or relax.

Smooth muscle plays an important role in many physiological processes, including digestion, circulation, respiration, and elimination. It can also contribute to various medical conditions, such as hypertension, gastrointestinal disorders, and genitourinary dysfunction, when it becomes overactive or underactive.

Muscarinic antagonists, also known as muscarinic receptor antagonists or parasympatholytics, are a class of drugs that block the action of acetylcholine at muscarinic receptors. Acetylcholine is a neurotransmitter that plays an important role in the parasympathetic nervous system, which helps to regulate various bodily functions such as heart rate, digestion, and respiration.

Muscarinic antagonists work by binding to muscarinic receptors, which are found in various organs throughout the body, including the eyes, lungs, heart, and gastrointestinal tract. By blocking the action of acetylcholine at these receptors, muscarinic antagonists can produce a range of effects depending on the specific receptor subtype that is affected.

For example, muscarinic antagonists may be used to treat conditions such as chronic obstructive pulmonary disease (COPD) and asthma by relaxing the smooth muscle in the airways and reducing bronchoconstriction. They may also be used to treat conditions such as urinary incontinence or overactive bladder by reducing bladder contractions.

Some common muscarinic antagonists include atropine, scopolamine, ipratropium, and tiotropium. It's important to note that these drugs can have significant side effects, including dry mouth, blurred vision, constipation, and confusion, especially when used in high doses or for prolonged periods of time.

A muscarinic M3 receptor is a type of G protein-coupled receptor (GPCR) that binds to the neurotransmitter acetylcholine. It is a subtype of muscarinic receptors, which are named after the muscarine mushroom alkaloid that can activate them.

The M3 receptor is widely expressed in various tissues and organs, including the smooth muscle of the gastrointestinal tract, urinary bladder, respiratory system, and vasculature. When activated by acetylcholine or muscarinic agonists, it triggers a range of intracellular signaling pathways that lead to various physiological responses, such as smooth muscle contraction, glandular secretion, and modulation of neurotransmitter release.

The M3 receptor is known to couple primarily to the Gq/11 family of G proteins, which activate phospholipase C (PLC) and increase intracellular calcium levels. This leads to smooth muscle contraction and other downstream effects. The M3 receptor also interacts with other signaling pathways, such as those involving adenylyl cyclase, mitogen-activated protein kinases (MAPKs), and ion channels.

Dysregulation of muscarinic M3 receptors has been implicated in various diseases, including gastrointestinal disorders, overactive bladder syndrome, asthma, and cardiovascular diseases. Therefore, selective modulation of this receptor subtype is a potential therapeutic strategy for these conditions.

Quinuclidinyl benzilate is a synthetic chemical compound that acts as a potent anticholinergic drug. Its chemical formula is C18H26N2O2. It is an odorless, white crystalline powder that is slightly soluble in water and more soluble in organic solvents.

Quinuclidinyl benzilate is a deliriant drug, which means it can cause delirium, confusion, hallucinations, and other altered mental states. It works by blocking the action of acetylcholine, a neurotransmitter in the brain that is involved in memory, attention, and perception.

This compound has been used in research as a tool to study the nervous system and has also been explored for its potential use as a chemical weapon. It is classified as a Schedule II controlled substance in the United States due to its high potential for abuse and the risk of severe psychological harm.

I must clarify that the term "Guinea Pigs" is not typically used in medical definitions. However, in colloquial or informal language, it may refer to people who are used as the first to try out a new medical treatment or drug. This is known as being a "test subject" or "in a clinical trial."

In the field of scientific research, particularly in studies involving animals, guinea pigs are small rodents that are often used as experimental subjects due to their size, cost-effectiveness, and ease of handling. They are not actually pigs from Guinea, despite their name's origins being unclear. However, they do not exactly fit the description of being used in human medical experiments.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

A muscarinic M2 receptor is a type of G protein-coupled receptor (GPCR) that binds to the neurotransmitter acetylcholine. It is one of five subtypes of muscarinic receptors (M1-M5) and is widely distributed throughout the body, particularly in the heart, smooth muscle, and exocrine glands.

The M2 receptor is coupled to the G protein inhibitory Gαi/o, which inhibits adenylyl cyclase activity and reduces intracellular cAMP levels. This leads to a variety of physiological responses, including negative chronotropy (slowing of heart rate) and negative inotropy (decreased contractility) in the heart, relaxation of smooth muscle in the bronchioles and gastrointestinal tract, and inhibition of exocrine gland secretion.

The M2 receptor is an important target for drugs used to treat a variety of conditions, including cardiovascular diseases, asthma, chronic obstructive pulmonary disease (COPD), and gastrointestinal disorders. Anticholinergic drugs such as atropine and ipratropium bind to the M2 receptor and block its activity, while muscarinic agonists such as bethanechol activate the receptor.

Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:

Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.

Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.

Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.

Pirenzepine is a medication that belongs to a class of drugs called anticholinergics or parasympatholytics. It works by blocking the action of acetylcholine, a neurotransmitter in the body, on certain types of muscarinic receptors.

Pirenzepine is primarily used to treat peptic ulcers and gastroesophageal reflux disease (GERD) by reducing the production of stomach acid. It may also be used to manage symptoms of irritable bowel syndrome, such as abdominal pain and diarrhea.

The medication is available in the form of tablets or gel for topical application. Side effects of pirenzepine may include dry mouth, blurred vision, constipation, dizziness, and difficulty urinating. It should be used with caution in people with glaucoma, benign prostatic hyperplasia, or other conditions that may be exacerbated by anticholinergic drugs.

It is important to note that this definition is for informational purposes only and should not be taken as medical advice. Always consult with a healthcare professional before starting any new medication.

N-Methylscopolamine is a anticholinergic drug, which means it blocks the action of acetylcholine, a neurotransmitter in the body. It is a derivative of scopolamine and is used to treat various conditions such as gastrointestinal disorders (such as gastritis, peptic ulcer), Parkinson's disease, motion sickness, and to reduce saliva production during surgical or diagnostic procedures.

It works by blocking the muscarinic receptors in the nervous system, which leads to a decrease in the secretion of fluids (such as saliva, sweat, stomach acid) and decreased muscle contractions in the gastrointestinal tract. N-Methylscopolamine can also cause side effects such as dizziness, dry mouth, blurred vision, and difficulty urinating.

The trachea, also known as the windpipe, is a tube-like structure in the respiratory system that connects the larynx (voice box) to the bronchi (the two branches leading to each lung). It is composed of several incomplete rings of cartilage and smooth muscle, which provide support and flexibility. The trachea plays a crucial role in directing incoming air to the lungs during inspiration and outgoing air to the larynx during expiration.

Parasympatholytics are a type of medication that blocks the action of the parasympathetic nervous system. The parasympathetic nervous system is responsible for the body's rest and digest response, which includes slowing the heart rate, increasing intestinal and glandular activity, and promoting urination and defecation.

Parasympatholytics work by selectively binding to muscarinic receptors, which are found in various organs throughout the body, including the heart, lungs, and digestive system. By blocking these receptors, parasympatholytics can cause a range of effects, such as an increased heart rate, decreased glandular secretions, and reduced intestinal motility.

Some common examples of parasympatholytics include atropine, scopolamine, and ipratropium. These medications are often used to treat conditions such as bradycardia (slow heart rate), excessive salivation, and gastrointestinal cramping or diarrhea. However, because they can have significant side effects, parasympatholytics are typically used only when necessary and under the close supervision of a healthcare provider.

The ileum is the third and final segment of the small intestine, located between the jejunum and the cecum (the beginning of the large intestine). It plays a crucial role in nutrient absorption, particularly for vitamin B12 and bile salts. The ileum is characterized by its thin, lined walls and the presence of Peyer's patches, which are part of the immune system and help surveil for pathogens.

Histamine is defined as a biogenic amine that is widely distributed throughout the body and is involved in various physiological functions. It is derived primarily from the amino acid histidine by the action of histidine decarboxylase. Histamine is stored in granules (along with heparin and proteases) within mast cells and basophils, and is released upon stimulation or degranulation of these cells.

Once released into the tissues and circulation, histamine exerts a wide range of pharmacological actions through its interaction with four types of G protein-coupled receptors (H1, H2, H3, and H4 receptors). Histamine's effects are diverse and include modulation of immune responses, contraction and relaxation of smooth muscle, increased vascular permeability, stimulation of gastric acid secretion, and regulation of neurotransmission.

Histamine is also a potent mediator of allergic reactions and inflammation, causing symptoms such as itching, sneezing, runny nose, and wheezing. Antihistamines are commonly used to block the actions of histamine at H1 receptors, providing relief from these symptoms.

Acetylcholine is a neurotransmitter, a type of chemical messenger that transmits signals across a chemical synapse from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. It is involved in both peripheral and central nervous system functions.

In the peripheral nervous system, acetylcholine acts as a neurotransmitter at the neuromuscular junction, where it transmits signals from motor neurons to activate muscles. Acetylcholine also acts as a neurotransmitter in the autonomic nervous system, where it is involved in both the sympathetic and parasympathetic systems.

In the central nervous system, acetylcholine plays a role in learning, memory, attention, and arousal. Disruptions in cholinergic neurotransmission have been implicated in several neurological disorders, including Alzheimer's disease, Parkinson's disease, and myasthenia gravis.

Acetylcholine is synthesized from choline and acetyl-CoA by the enzyme choline acetyltransferase and is stored in vesicles at the presynaptic terminal of the neuron. When a nerve impulse arrives, the vesicles fuse with the presynaptic membrane, releasing acetylcholine into the synapse. The acetylcholine then binds to receptors on the postsynaptic membrane, triggering a response in the target cell. Acetylcholine is subsequently degraded by the enzyme acetylcholinesterase, which terminates its action and allows for signal transduction to be repeated.

The parotid gland is the largest of the major salivary glands. It is a bilobed, accessory digestive organ that secretes serous saliva into the mouth via the parotid duct (Stensen's duct), located near the upper second molar tooth. The parotid gland is primarily responsible for moistening and lubricating food to aid in swallowing and digestion.

Anatomically, the parotid gland is located in the preauricular region, extending from the zygomatic arch superiorly to the angle of the mandible inferiorly, and from the masseter muscle anteriorly to the sternocleidomastoid muscle posteriorly. It is enclosed within a fascial capsule and has a rich blood supply from the external carotid artery and a complex innervation pattern involving both parasympathetic and sympathetic fibers.

Parotid gland disorders can include salivary gland stones (sialolithiasis), infections, inflammatory conditions, benign or malignant tumors, and autoimmune diseases such as Sjögren's syndrome.

Cholinergic agents are a class of drugs that mimic the action of acetylcholine, a neurotransmitter in the body that is involved in the transmission of nerve impulses. These agents work by either increasing the amount of acetylcholine in the synapse (the space between two neurons) or enhancing its action on receptors.

Cholinergic agents can be classified into two main categories: direct-acting and indirect-acting. Direct-acting cholinergic agents, also known as parasympathomimetics, directly stimulate muscarinic and nicotinic acetylcholine receptors. Examples of direct-acting cholinergic agents include pilocarpine, bethanechol, and carbamate.

Indirect-acting cholinergic agents, on the other hand, work by inhibiting the enzyme acetylcholinesterase, which is responsible for breaking down acetylcholine in the synapse. By inhibiting this enzyme, indirect-acting cholinergic agents increase the amount of acetylcholine available to stimulate receptors. Examples of indirect-acting cholinergic agents include physostigmine, neostigmine, and edrophonium.

Cholinergic agents are used in the treatment of a variety of medical conditions, including myasthenia gravis, Alzheimer's disease, glaucoma, and gastrointestinal disorders. However, they can also have significant side effects, such as bradycardia, bronchoconstriction, and increased salivation, due to their stimulation of muscarinic receptors. Therefore, they must be used with caution and under the close supervision of a healthcare provider.

A muscarinic acetylcholine receptor (mAChR) is a type of G protein-coupled receptor (GPCR) that binds the neurotransmitter acetylcholine and mediates various responses in the body. The M1 subtype of muscarinic receptors (CHRM1) is widely distributed throughout the central and peripheral nervous system, with particularly high densities found in the cerebral cortex, hippocampus, striatum, and autonomic ganglia.

Muscarinic M1 receptors are coupled to G proteins of the Gq/11 family, which activate phospholipase C (PLC) upon receptor activation. This leads to the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol trisphosphate (IP3) and diacylglycerol (DAG), which further trigger intracellular signaling cascades.

The activation of muscarinic M1 receptors is involved in several physiological processes, including:

* Cognitive functions such as learning, memory, and attention
* Excitatory neurotransmission in the hippocampus
* Regulation of smooth muscle tone, particularly in the gastrointestinal tract and airways
* Secretion of various hormones and enzymes, including those involved in insulin release and lipid metabolism

Dysregulation of muscarinic M1 receptors has been implicated in several pathological conditions, such as Alzheimer's disease, Parkinson's disease, schizophrenia, and irritable bowel syndrome. Therefore, targeting these receptors with pharmacological agents presents a potential therapeutic strategy for treating these disorders.

Inositol phosphates are a family of molecules that consist of an inositol ring, which is a six-carbon heterocyclic compound, linked to one or more phosphate groups. These molecules play important roles as intracellular signaling intermediates and are involved in various cellular processes such as cell growth, differentiation, and metabolism.

Inositol hexakisphosphate (IP6), also known as phytic acid, is a form of inositol phosphate that is found in plant-based foods. IP6 has the ability to bind to minerals such as calcium, magnesium, and iron, which can reduce their bioavailability in the body.

Inositol phosphates have been implicated in several diseases, including cancer, diabetes, and neurodegenerative disorders. For example, altered levels of certain inositol phosphates have been observed in cancer cells, suggesting that they may play a role in tumor growth and progression. Additionally, mutations in enzymes involved in the metabolism of inositol phosphates have been associated with several genetic diseases.

Phosphatidylinositols (PIs) are a type of phospholipid that are abundant in the cell membrane. They contain a glycerol backbone, two fatty acid chains, and a head group consisting of myo-inositol, a cyclic sugar molecule, linked to a phosphate group.

Phosphatidylinositols can be phosphorylated at one or more of the hydroxyl groups on the inositol ring, forming various phosphoinositides (PtdInsPs) with different functions. These signaling molecules play crucial roles in regulating cellular processes such as membrane trafficking, cytoskeletal organization, and signal transduction pathways that control cell growth, differentiation, and survival.

Phosphatidylinositol 4,5-bisphosphate (PIP2) is a prominent phosphoinositide involved in the regulation of ion channels, enzymes, and cytoskeletal proteins. Upon activation of certain receptors, PIP2 can be cleaved by the enzyme phospholipase C into diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (InsP3), which act as second messengers to trigger downstream signaling events.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Cholinergic receptors are a type of receptor in the body that are activated by the neurotransmitter acetylcholine. Acetylcholine is a chemical that nerve cells use to communicate with each other and with muscles. There are two main types of cholinergic receptors: muscarinic and nicotinic.

Muscarinic receptors are found in the heart, smooth muscle, glands, and the central nervous system. They are activated by muscarine, a type of alkaloid found in certain mushrooms. When muscarinic receptors are activated, they can cause changes in heart rate, blood pressure, and other bodily functions.

Nicotinic receptors are found in the nervous system and at the junction between nerves and muscles (the neuromuscular junction). They are activated by nicotine, a type of alkaloid found in tobacco plants. When nicotinic receptors are activated, they can cause the release of neurotransmitters and the contraction of muscles.

Cholinergic receptors play an important role in many physiological processes, including learning, memory, and movement. They are also targets for drugs used to treat a variety of medical conditions, such as Alzheimer's disease, Parkinson's disease, and myasthenia gravis (a disorder that causes muscle weakness).

The urinary bladder is a muscular, hollow organ in the pelvis that stores urine before it is released from the body. It expands as it fills with urine and contracts when emptying. The typical adult bladder can hold between 400 to 600 milliliters of urine for about 2-5 hours before the urge to urinate occurs. The wall of the bladder contains several layers, including a mucous membrane, a layer of smooth muscle (detrusor muscle), and an outer fibrous adventitia. The muscles of the bladder neck and urethra remain contracted to prevent leakage of urine during filling, and they relax during voiding to allow the urine to flow out through the urethra.

Oxotremorine is a muscarinic receptor agonist, which means it binds to and activates muscarinic acetylcholine receptors. These receptors are found in the central and peripheral nervous system and are involved in various physiological functions, including cognition, motivation, reward, motor control, and sensory processing.

Oxotremorine is primarily used in research settings to study the role of muscarinic receptors in different physiological processes and diseases. It has been shown to produce effects similar to those caused by natural neurotransmitter acetylcholine, such as increased salivation, sweating, and gastrointestinal motility.

In addition, oxotremorine has been investigated for its potential therapeutic use in the treatment of various neurological disorders, including Alzheimer's disease, Parkinson's disease, and schizophrenia. However, its clinical use is limited due to its side effects, such as nausea, vomiting, diarrhea, and abdominal cramps.

Potassium is a essential mineral and an important electrolyte that is widely distributed in the human body. The majority of potassium in the body (approximately 98%) is found within cells, with the remaining 2% present in blood serum and other bodily fluids. Potassium plays a crucial role in various physiological processes, including:

1. Regulation of fluid balance and maintenance of normal blood pressure through its effects on vascular tone and sodium excretion.
2. Facilitation of nerve impulse transmission and muscle contraction by participating in the generation and propagation of action potentials.
3. Protein synthesis, enzyme activation, and glycogen metabolism.
4. Regulation of acid-base balance through its role in buffering systems.

The normal serum potassium concentration ranges from 3.5 to 5.0 mEq/L (milliequivalents per liter) or mmol/L (millimoles per liter). Potassium levels outside this range can have significant clinical consequences, with both hypokalemia (low potassium levels) and hyperkalemia (high potassium levels) potentially leading to serious complications such as cardiac arrhythmias, muscle weakness, and respiratory failure.

Potassium is primarily obtained through the diet, with rich sources including fruits (e.g., bananas, oranges, and apricots), vegetables (e.g., leafy greens, potatoes, and tomatoes), legumes, nuts, dairy products, and meat. In cases of deficiency or increased needs, potassium supplements may be recommended under the guidance of a healthcare professional.

'Diamines' are organic compounds containing two amino groups (-NH2) in their molecular structure. The term 'diamine' itself does not have a specific medical definition, but it is used in the context of chemistry and biochemistry.

Diamines can be classified based on the number of carbon atoms between the two amino groups. For example, ethylenediamine and propylenediamine are diamines with one and two methylene (-CH2-) groups, respectively.

In medicine, certain diamines may have biological significance. For instance, putrescine and cadaverine are polyamines that are produced during the decomposition of animal tissues and can be found in necrotic or infected tissues. These compounds have been implicated in various pathological processes, including inflammation, oxidative stress, and cancer progression.

It is important to note that while some diamines may have medical relevance, the term 'diamines' itself does not have a specific medical definition.

Sincalide is a synthetic hormone that stimulates the contraction of the gallbladder and the release of digestive enzymes from the pancreas. It is used in diagnostic procedures to help diagnose conditions such as gallstones or obstructions of the bile ducts.

Sincalide is a synthetic form of cholecystokinin (CCK), a hormone that is naturally produced in the body and stimulates the contraction of the gallbladder and the release of digestive enzymes from the pancreas. When sincalide is administered, it mimics the effects of CCK and causes the gallbladder to contract and release bile into the small intestine. This can help doctors see if there are any obstructions or abnormalities in the bile ducts or gallbladder.

Sincalide is usually given as an injection, and its effects can be monitored through imaging tests such as ultrasound or CT scans. It is important to note that sincalide should only be used under the supervision of a healthcare professional, as it can cause side effects such as abdominal pain, nausea, and vomiting.

Parietal cells, also known as oxyntic cells, are a type of cell found in the gastric glands of the stomach lining. They play a crucial role in digestion by releasing hydrochloric acid and intrinsic factor into the stomach lumen. Hydrochloric acid is essential for breaking down food particles and creating an acidic environment that kills most bacteria, while intrinsic factor is necessary for the absorption of vitamin B12 in the small intestine. Parietal cells are stimulated by histamine, acetylcholine, and gastrin to release their secretory products.

Isoproterenol is a medication that belongs to a class of drugs called beta-adrenergic agonists. Medically, it is defined as a synthetic catecholamine with both alpha and beta adrenergic receptor stimulating properties. It is primarily used as a bronchodilator to treat conditions such as asthma and chronic obstructive pulmonary disease (COPD) by relaxing the smooth muscles in the airways, thereby improving breathing.

Isoproterenol can also be used in the treatment of bradycardia (abnormally slow heart rate), cardiac arrest, and heart blocks by increasing the heart rate and contractility. However, due to its non-selective beta-agonist activity, it may cause various side effects such as tremors, palpitations, and increased blood pressure. Its use is now limited due to the availability of more selective and safer medications.

Muscle relaxation, in a medical context, refers to the process of reducing tension and promoting relaxation in the skeletal muscles. This can be achieved through various techniques, including progressive muscle relaxation (PMR), where individuals consciously tense and then release specific muscle groups in a systematic manner.

PMR has been shown to help reduce anxiety, stress, and muscle tightness, and improve overall well-being. It is often used as a complementary therapy in conjunction with other treatments for conditions such as chronic pain, headaches, and insomnia.

Additionally, muscle relaxation can also be facilitated through pharmacological interventions, such as the use of muscle relaxant medications. These drugs work by inhibiting the transmission of signals between nerves and muscles, leading to a reduction in muscle tone and spasticity. They are commonly used to treat conditions such as multiple sclerosis, cerebral palsy, and spinal cord injuries.

The Parasympathetic Nervous System (PNS) is the part of the autonomic nervous system that primarily controls vegetative functions during rest, relaxation, and digestion. It is responsible for the body's "rest and digest" activities including decreasing heart rate, lowering blood pressure, increasing digestive activity, and stimulating sexual arousal. The PNS utilizes acetylcholine as its primary neurotransmitter and acts in opposition to the Sympathetic Nervous System (SNS), which is responsible for the "fight or flight" response.

Hexamethonium compounds are a type of ganglionic blocker, which are medications that block the transmission of nerve impulses at the ganglia ( clusters of nerve cells) in the autonomic nervous system. These compounds contain hexamethonium as the active ingredient, which is a compound with the chemical formula C16H32N2O4.

Hexamethonium works by blocking the nicotinic acetylcholine receptors at the ganglia, which prevents the release of neurotransmitters and ultimately inhibits the transmission of nerve impulses. This can have various effects on the body, depending on which part of the autonomic nervous system is affected.

Hexamethonium compounds were once used to treat hypertension (high blood pressure), but they are rarely used today due to their numerous side effects and the availability of safer and more effective medications. Some of the side effects associated with hexamethonium include dry mouth, blurred vision, constipation, difficulty urinating, and dizziness upon standing.

The lacrimal apparatus is a complex system in the eye that produces, stores, and drains tears. It consists of several components including:

1. Lacrimal glands: These are located in the upper outer part of the eyelid and produce tears to keep the eye surface moist and protected from external agents.
2. Tear ducts (lacrimal canaliculi): These are small tubes that drain tears from the surface of the eye into the lacrimal sac.
3. Lacrimal sac: This is a small pouch-like structure located in the inner part of the eyelid, which collects tears from the tear ducts and drains them into the nasolacrimal duct.
4. Nasolacrimal duct: This is a tube that runs from the lacrimal sac to the nose and drains tears into the nasal cavity.

The lacrimal apparatus helps maintain the health and comfort of the eye by keeping it lubricated, protecting it from infection, and removing any foreign particles or debris.

Membrane potential is the electrical potential difference across a cell membrane, typically for excitable cells such as nerve and muscle cells. It is the difference in electric charge between the inside and outside of a cell, created by the selective permeability of the cell membrane to different ions. The resting membrane potential of a typical animal cell is around -70 mV, with the interior being negative relative to the exterior. This potential is generated and maintained by the active transport of ions across the membrane, primarily through the action of the sodium-potassium pump. Membrane potentials play a crucial role in many physiological processes, including the transmission of nerve impulses and the contraction of muscle cells.

Eccrine glands are the most numerous type of sweat glands in the human body, found in virtually all skin locations. They play a crucial role in thermoregulation by producing a watery sweat that cools the body when it evaporates on the skin surface. These glands are distributed over the entire body, with a higher concentration on the soles of the feet, palms of the hands, and forehead.

Structurally, eccrine glands consist of two main parts: the coiled secretory portion located in the dermis and the straight duct that extends through the dermis and epidermis to reach the skin surface. The secretory portion is lined with a simple cuboidal epithelium, while the duct is lined with a simple squamous or low cuboidal epithelium.

Eccrine glands are stimulated to produce sweat by the activation of the sympathetic nervous system, particularly through the release of acetylcholine at the neuro-glandular junction. The sweat produced is primarily water with small amounts of electrolytes, such as sodium, chloride, and potassium. This composition helps maintain the body's electrolyte balance while facilitating heat loss during physical exertion or in hot environments.

Physostigmine is a medication that belongs to a class of drugs called cholinesterase inhibitors. It works by blocking the breakdown of a neurotransmitter called acetylcholine, which is important for communication between nerves and muscles. This results in an increase in acetylcholine levels in the body, improving nerve impulse transmission and helping to restore normal muscle function.

Physostigmine is used in the treatment of certain medical conditions that are caused by a deficiency of acetylcholine, such as myasthenia gravis, which is a neuromuscular disorder characterized by weakness and fatigue of the muscles. It may also be used to reverse the effects of certain medications that block the action of acetylcholine, such as anticholinergics, which are sometimes used in anesthesia or to treat conditions like Parkinson's disease.

It is important to note that physostigmine should only be used under the close supervision of a healthcare provider, as it can have serious side effects if not used properly.

Aminopyrine is a type of medication known as a non-opioid analgesic, which is used to relieve pain and reduce fever. It is an antipyretic and analgesic drug that was widely used in the past, but its use has been limited or discontinued in many countries due to the risk of rare but serious side effects such as agranulocytosis (a severe decrease in white blood cells), which can make individuals more susceptible to infections.

Chemically, aminopyrine is an aromatic heterocyclic compound containing a pyridine ring substituted with an amino group and a phenyl group. It works by inhibiting the enzyme cyclooxygenase (COX), which is involved in the production of prostaglandins, chemicals that mediate pain and inflammation. By reducing prostaglandin levels, aminopyrine helps to alleviate pain and reduce fever.

It's important to note that due to its potential side effects, aminopyrine is not commonly used in modern medical practice, and other safer and more effective medications are available for pain relief and fever reduction.

Cholinergic antagonists, also known as anticholinergics or parasympatholytics, are a class of drugs that block the action of the neurotransmitter acetylcholine in the nervous system. They achieve this by binding to and blocking the activation of muscarinic acetylcholine receptors, which are found in various organs throughout the body, including the eyes, lungs, heart, gastrointestinal tract, and urinary bladder.

The blockade of these receptors results in a range of effects depending on the specific organ system involved. For example, cholinergic antagonists can cause mydriasis (dilation of the pupils), cycloplegia (paralysis of the ciliary muscle of the eye), tachycardia (rapid heart rate), reduced gastrointestinal motility and secretion, urinary retention, and respiratory tract smooth muscle relaxation.

Cholinergic antagonists are used in a variety of clinical settings, including the treatment of conditions such as Parkinson's disease, chronic obstructive pulmonary disease (COPD), asthma, gastrointestinal disorders, and urinary incontinence. Some common examples of cholinergic antagonists include atropine, scopolamine, ipratropium, and oxybutynin.

It's important to note that cholinergic antagonists can have significant side effects, particularly when used in high doses or in combination with other medications that affect the nervous system. These side effects can include confusion, memory impairment, hallucinations, delirium, and blurred vision. Therefore, it's essential to use these drugs under the close supervision of a healthcare provider and to follow their instructions carefully.

Colforsin is a drug that belongs to a class of medications called phosphodiesterase inhibitors. It works by increasing the levels of a chemical called cyclic AMP (cyclic adenosine monophosphate) in the body, which helps to relax and widen blood vessels.

Colforsin is not approved for use in humans in many countries, including the United States. However, it has been used in research settings to study its potential effects on heart function and other physiological processes. In animals, colforsin has been shown to have positive inotropic (contractility-enhancing) and lusitropic (relaxation-enhancing) effects on the heart, making it a potential therapeutic option for heart failure and other cardiovascular conditions.

It is important to note that while colforsin has shown promise in preclinical studies, more research is needed to establish its safety and efficacy in humans. Therefore, it should only be used under the supervision of a qualified healthcare professional and in the context of a clinical trial or research study.

Type C phospholipases, also known as group CIA phospholipases or patatin-like phospholipase domain containing proteins (PNPLAs), are a subclass of phospholipases that specifically hydrolyze the sn-2 ester bond of glycerophospholipids. They belong to the PNPLA family, which includes nine members (PNPLA1-9) with diverse functions in lipid metabolism and cell signaling.

Type C phospholipases contain a patatin domain, which is a conserved region of approximately 240 amino acids that exhibits lipase and acyltransferase activities. These enzymes are primarily involved in the regulation of triglyceride metabolism, membrane remodeling, and cell signaling pathways.

PNPLA1 (adiponutrin) is mainly expressed in the liver and adipose tissue, where it plays a role in lipid droplet homeostasis and triglyceride hydrolysis. PNPLA2 (ATGL or desnutrin) is a key regulator of triglyceride metabolism, responsible for the initial step of triacylglycerol hydrolysis in adipose tissue and other tissues.

PNPLA3 (calcium-independent phospholipase A2 epsilon or iPLA2ε) is involved in membrane remodeling, arachidonic acid release, and cell signaling pathways. Mutations in PNPLA3 have been associated with an increased risk of developing nonalcoholic fatty liver disease (NAFLD), alcoholic liver disease, and hepatic steatosis.

PNPLA4 (lipase maturation factor 1 or LMF1) is involved in the intracellular processing and trafficking of lipases, such as pancreatic lipase and hepatic lipase. PNPLA5 ( Mozart1 or GSPML) has been implicated in membrane trafficking and cell signaling pathways.

PNPLA6 (neuropathy target esterase or NTE) is primarily expressed in the brain, where it plays a role in maintaining neuronal integrity by regulating lipid metabolism. Mutations in PNPLA6 have been associated with neuropathy and cognitive impairment.

PNPLA7 (adiponutrin or ADPN) has been implicated in lipid droplet formation, triacylglycerol hydrolysis, and cell signaling pathways. Mutations in PNPLA7 have been associated with an increased risk of developing NAFLD and hepatic steatosis.

PNPLA8 (diglyceride lipase or DGLα) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA9 (calcium-independent phospholipase A2 gamma or iPLA2γ) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA10 (calcium-independent phospholipase A2 delta or iPLA2δ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA11 (calcium-independent phospholipase A2 epsilon or iPLA2ε) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA12 (calcium-independent phospholipase A2 zeta or iPLA2ζ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA13 (calcium-independent phospholipase A2 eta or iPLA2η) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA14 (calcium-independent phospholipase A2 theta or iPLA2θ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA15 (calcium-independent phospholipase A2 iota or iPLA2ι) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA16 (calcium-independent phospholipase A2 kappa or iPLA2κ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA17 (calcium-independent phospholipase A2 lambda or iPLA2λ) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA18 (calcium-independent phospholipase A2 mu or iPLA2μ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA19 (calcium-independent phospholipase A2 nu or iPLA2ν) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA20 (calcium-independent phospholipase A2 xi or iPLA2ξ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA21 (calcium-independent phospholipase A2 omicron or iPLA2ο) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA22 (calcium-independent phospholipase A2 pi or iPLA2π) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA23 (calcium-independent phospholipase A2 rho or iPLA2ρ) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA24 (calcium-independent phospholipase A2 sigma or iPLA2σ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA25 (calcium-independent phospholipase A2 tau or iPLA2τ) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA26 (calcium-independent phospholipase A2 upsilon or iPLA2υ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA27 (calcium-independent phospholipase A2 phi or iPLA2φ) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA28 (calcium-independent phospholipase A2 chi or iPLA2χ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA29 (calcium-independent phospholipase A2 psi or iPLA2ψ) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA30 (calcium-independent phospholipase A2 omega or iPLA2ω) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA31 (calcium-independent phospholipase A2 pi or iPLA2π) has been implicated in membrane remodeling, arachidonic acid release, and cell signaling pathways.

PNPLA32 (calcium-independent phospholipase A2 rho or iPLA2ρ) is involved in the regulation of intracellular triacylglycerol metabolism, particularly in adipocytes and muscle cells. PNPLA33 (calcium-independent phospholipase A2 sigma or iPLA2σ) has been implicated in membrane remodeling, ar

Electric stimulation, also known as electrical nerve stimulation or neuromuscular electrical stimulation, is a therapeutic treatment that uses low-voltage electrical currents to stimulate nerves and muscles. It is often used to help manage pain, promote healing, and improve muscle strength and mobility. The electrical impulses can be delivered through electrodes placed on the skin or directly implanted into the body.

In a medical context, electric stimulation may be used for various purposes such as:

1. Pain management: Electric stimulation can help to block pain signals from reaching the brain and promote the release of endorphins, which are natural painkillers produced by the body.
2. Muscle rehabilitation: Electric stimulation can help to strengthen muscles that have become weak due to injury, illness, or surgery. It can also help to prevent muscle atrophy and improve range of motion.
3. Wound healing: Electric stimulation can promote tissue growth and help to speed up the healing process in wounds, ulcers, and other types of injuries.
4. Urinary incontinence: Electric stimulation can be used to strengthen the muscles that control urination and reduce symptoms of urinary incontinence.
5. Migraine prevention: Electric stimulation can be used as a preventive treatment for migraines by applying electrical impulses to specific nerves in the head and neck.

It is important to note that electric stimulation should only be administered under the guidance of a qualified healthcare professional, as improper use can cause harm or discomfort.

The pons is a part of the brainstem that lies between the medulla oblongata and the midbrain. Its name comes from the Latin word "ponte" which means "bridge," as it serves to connect these two regions of the brainstem. The pons contains several important structures, including nerve fibers that carry signals between the cerebellum (the part of the brain responsible for coordinating muscle movements) and the rest of the nervous system. It also contains nuclei (clusters of neurons) that help regulate various functions such as respiration, sleep, and facial movements.

Potassium chloride is an essential electrolyte that is often used in medical settings as a medication. It's a white, crystalline salt that is highly soluble in water and has a salty taste. In the body, potassium chloride plays a crucial role in maintaining fluid and electrolyte balance, nerve function, and muscle contraction.

Medically, potassium chloride is commonly used to treat or prevent low potassium levels (hypokalemia) in the blood. Hypokalemia can occur due to various reasons such as certain medications, kidney diseases, vomiting, diarrhea, or excessive sweating. Potassium chloride is available in various forms, including tablets, capsules, and liquids, and it's usually taken by mouth.

It's important to note that potassium chloride should be used with caution and under the supervision of a healthcare provider, as high levels of potassium (hyperkalemia) can be harmful and even life-threatening. Hyperkalemia can cause symptoms such as muscle weakness, irregular heartbeat, and cardiac arrest.

Propylbenzilylcholine mustard is not a medical term, but it is a chemical compound that has been used in research and development. It's a type of muscarinic receptor agonist, which means it binds to and activates muscarinic acetylcholine receptors, a type of receptor found in the nervous system.

In a medical context, this compound may be used in research to study the functions of the muscarinic receptors or to develop new medications that target these receptors. However, it is not currently used as a medication in clinical practice.

It's important to note that Propylbenzilylcholine mustard is also known as a "receptor agonist" and has been used in research as a tool to stimulate muscarinic receptors. It's not a drug, but a compound used in laboratory settings for scientific studies.

Scopolamine derivatives are a class of compounds that are chemically related to scopolamine, a natural alkaloid found in certain plants such as nightshade. These derivatives share similar structural and pharmacological properties with scopolamine, which is a muscarinic antagonist. They block the action of acetylcholine, a neurotransmitter, at muscarinic receptors in the nervous system.

Scopolamine derivatives are commonly used in medical settings as anticholinergics, which have various therapeutic applications. They can be used to treat conditions such as motion sickness, nausea and vomiting, Parkinson's disease, and certain types of nerve agent poisoning. Some examples of scopolamine derivatives include hyoscine, pirenzepine, and telenzepine.

It is important to note that scopolamine derivatives can have significant side effects, including dry mouth, blurred vision, dizziness, and cognitive impairment. Therefore, they should be used with caution and under the close supervision of a healthcare provider.

Sugar phosphates are organic compounds that play crucial roles in various biological processes, particularly in the field of genetics and molecular biology. They are formed by the attachment of a phosphate group to a sugar molecule, most commonly to the 5-carbon sugar ribose or deoxyribose.

In genetics, sugar phosphates form the backbone of nucleic acids, such as DNA and RNA. In DNA, the sugar phosphate backbone consists of alternating deoxyribose (a sugar) and phosphate groups, linked together by covalent bonds between the 5' carbon atom of one sugar molecule and the 3' carbon atom of another sugar molecule. This forms a long, twisted ladder-like structure known as a double helix.

Similarly, in RNA, the sugar phosphate backbone is formed by ribose (a sugar) and phosphate groups, creating a single-stranded structure that can fold back on itself to form complex shapes. These sugar phosphate backbones provide structural support for the nucleic acids and help to protect the genetic information stored within them.

Sugar phosphates also play important roles in energy metabolism, as they are involved in the formation and breakdown of high-energy compounds such as ATP (adenosine triphosphate) and GTP (guanosine triphosphate). These molecules serve as energy currency for cells, storing and releasing energy as needed to power various cellular processes.

Miotics, also known as parasympathomimetics or cholinergic agents, are a class of medications that stimulate the parasympathetic nervous system. They work by activating muscarinic receptors, which are found in various organs throughout the body, including the eye. In the eye, miotics cause contraction of the circular muscle of the iris, resulting in pupillary constriction (miosis). This action can help to reduce intraocular pressure in patients with glaucoma.

Miotics may also have other effects on the eye, such as accommodation (focusing) and decreasing the production of aqueous humor. Some examples of miotics include pilocarpine, carbachol, and ecothiopate. It's important to note that the use of miotics can have side effects, including blurred vision, headache, and brow ache.

Inositol 1,4,5-trisphosphate (IP3) is a intracellular signaling molecule that plays a crucial role in the release of calcium ions from the endoplasmic reticulum into the cytoplasm. It is a second messenger, which means it relays signals received by a cell's surface receptors to various effector proteins within the cell. IP3 is produced through the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) by activated phospholipase C (PLC) enzymes in response to extracellular signals such as hormones and neurotransmitters. The binding of IP3 to its receptor on the endoplasmic reticulum triggers the release of calcium ions, which then activates various cellular processes like gene expression, metabolism, and muscle contraction.

Chlorides are simple inorganic ions consisting of a single chlorine atom bonded to a single charged hydrogen ion (H+). Chloride is the most abundant anion (negatively charged ion) in the extracellular fluid in the human body. The normal range for chloride concentration in the blood is typically between 96-106 milliequivalents per liter (mEq/L).

Chlorides play a crucial role in maintaining electrical neutrality, acid-base balance, and osmotic pressure in the body. They are also essential for various physiological processes such as nerve impulse transmission, maintenance of membrane potentials, and digestion (as hydrochloric acid in the stomach).

Chloride levels can be affected by several factors, including diet, hydration status, kidney function, and certain medical conditions. Increased or decreased chloride levels can indicate various disorders, such as dehydration, kidney disease, Addison's disease, or diabetes insipidus. Therefore, monitoring chloride levels is essential for assessing a person's overall health and diagnosing potential medical issues.

Pilocarpine is a cholinergic agonist, which means it stimulates the parasympathetic nervous system by binding to muscarinic receptors. It is primarily used in the treatment of dry mouth (xerostomia) caused by radiation therapy or Sjögren's syndrome, as well as in the management of glaucoma due to its ability to construct the pupils and reduce intraocular pressure. Pilocarpine can also be used to treat certain cardiovascular conditions and chronic bronchitis. It is available in various forms, including tablets, ophthalmic solutions, and topical gels.

A chemical stimulation in a medical context refers to the process of activating or enhancing physiological or psychological responses in the body using chemical substances. These chemicals can interact with receptors on cells to trigger specific reactions, such as neurotransmitters and hormones that transmit signals within the nervous system and endocrine system.

Examples of chemical stimulation include the use of medications, drugs, or supplements that affect mood, alertness, pain perception, or other bodily functions. For instance, caffeine can chemically stimulate the central nervous system to increase alertness and decrease feelings of fatigue. Similarly, certain painkillers can chemically stimulate opioid receptors in the brain to reduce the perception of pain.

It's important to note that while chemical stimulation can have therapeutic benefits, it can also have adverse effects if used improperly or in excessive amounts. Therefore, it's essential to follow proper dosing instructions and consult with a healthcare provider before using any chemical substances for stimulation purposes.

Cyclic adenosine monophosphate (cAMP) is a key secondary messenger in many biological processes, including the regulation of metabolism, gene expression, and cellular excitability. It is synthesized from adenosine triphosphate (ATP) by the enzyme adenylyl cyclase and is degraded by the enzyme phosphodiesterase.

In the body, cAMP plays a crucial role in mediating the effects of hormones and neurotransmitters on target cells. For example, when a hormone binds to its receptor on the surface of a cell, it can activate a G protein, which in turn activates adenylyl cyclase to produce cAMP. The increased levels of cAMP then activate various effector proteins, such as protein kinases, which go on to regulate various cellular processes.

Overall, the regulation of cAMP levels is critical for maintaining proper cellular function and homeostasis, and abnormalities in cAMP signaling have been implicated in a variety of diseases, including cancer, diabetes, and neurological disorders.

Sweat glands are specialized tubular structures in the skin that produce and secrete sweat, also known as perspiration. They are part of the body's thermoregulatory system, helping to maintain optimal body temperature by releasing water and heat through evaporation. There are two main types of sweat glands: eccrine and apocrine.

1. Eccrine sweat glands: These are distributed throughout the body, with a higher concentration on areas like the palms, soles, and forehead. They are responsible for producing a watery, odorless sweat that primarily helps to cool down the body through evaporation.

2. Apocrine sweat glands: These are mainly found in the axillary (armpit) region and around the anogenital area. They become active during puberty and produce a thick, milky fluid that does not have a strong odor on its own but can mix with bacteria on the skin's surface, leading to body odor.

Sweat glands are controlled by the autonomic nervous system, meaning they function involuntarily in response to various stimuli such as emotions, physical activity, or changes in environmental temperature.

Protein Kinase C (PKC) is a family of serine-threonine kinases that play crucial roles in various cellular signaling pathways. These enzymes are activated by second messengers such as diacylglycerol (DAG) and calcium ions (Ca2+), which result from the activation of cell surface receptors like G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs).

Once activated, PKC proteins phosphorylate downstream target proteins, thereby modulating their activities. This regulation is involved in numerous cellular processes, including cell growth, differentiation, apoptosis, and membrane trafficking. There are at least 10 isoforms of PKC, classified into three subfamilies based on their second messenger requirements and structural features: conventional (cPKC; α, βI, βII, and γ), novel (nPKC; δ, ε, η, and θ), and atypical (aPKC; ζ and ι/λ). Dysregulation of PKC signaling has been implicated in several diseases, such as cancer, diabetes, and neurological disorders.

Pertussis toxin is an exotoxin produced by the bacterium Bordetella pertussis, which is responsible for causing whooping cough in humans. This toxin has several effects on the host organism, including:

1. Adenylyl cyclase activation: Pertussis toxin enters the host cell and modifies a specific G protein (Gαi), leading to the continuous activation of adenylyl cyclase. This results in increased levels of intracellular cAMP, which disrupts various cellular processes.
2. Inhibition of immune response: Pertussis toxin impairs the host's immune response by inhibiting the migration and function of immune cells like neutrophils and macrophages. It also interferes with antigen presentation and T-cell activation, making it difficult for the body to clear the infection.
3. Increased inflammation: The continuous activation of adenylyl cyclase by pertussis toxin leads to increased production of proinflammatory cytokines, contributing to the severe coughing fits and other symptoms associated with whooping cough.

Pertussis toxin is an essential virulence factor for Bordetella pertussis, and its effects contribute significantly to the pathogenesis of whooping cough. Vaccination against pertussis includes inactivated or genetically detoxified forms of pertussis toxin, which provide immunity without causing disease symptoms.

Tubocurarine is a type of neuromuscular blocking agent, specifically a non-depolarizing skeletal muscle relaxant. It works by competitively binding to the nicotinic acetylcholine receptors at the motor endplate, thereby preventing the binding of acetylcholine and inhibiting muscle contraction. Tubocurarine is derived from the South American curare plant and has been used in anesthesia to facilitate intubation and mechanical ventilation during surgery. However, its use has largely been replaced by newer, more selective agents due to its potential for histamine release and cardiovascular effects.

I apologize for the confusion, but "Thapsia" is not a medical term that refers to a specific condition or disease. Thapsia is actually a genus of plants in the family Apiaceae, also known as the carrot family. Some species of Thapsia contain a compound called thapsigargin, which has been studied for its potential medicinal properties, particularly in cancer research. However, it's important to note that this compound can also be highly toxic and should not be ingested without proper medical supervision.

If you have any questions related to medical terminology or health concerns, I would be happy to try and help answer them for you.

Decamethonium compounds are a type of neuromuscular blocking agent used in anesthesia to induce paralysis and relaxation of skeletal muscles. These compounds work by binding to and inhibiting the action of acetylcholine receptors at the neuromuscular junction, which is the site where nerve impulses are transmitted to muscle fibers.

Decamethonium bromide is a commonly used example of a decamethonium compound. It has a rapid onset of action and causes paralysis that lasts for several minutes. This makes it useful for procedures such as endotracheal intubation, where it is important to temporarily paralyze the muscles of the throat to facilitate insertion of a breathing tube.

It's important to note that decamethonium compounds do not have any analgesic or sedative effects, so they are typically used in conjunction with other medications that provide pain relief and sedation during surgical procedures. Additionally, because these compounds can cause respiratory depression, patients must be carefully monitored and provided with mechanical ventilation as needed during their use.

Virulence factors in Bordetella pertussis, the bacterium that causes whooping cough, refer to the characteristics or components of the organism that contribute to its ability to cause disease. These virulence factors include:

1. Pertussis Toxin (PT): A protein exotoxin that inhibits the immune response and affects the nervous system, leading to the characteristic paroxysmal cough of whooping cough.
2. Adenylate Cyclase Toxin (ACT): A toxin that increases the levels of cAMP in host cells, disrupting their function and contributing to the pathogenesis of the disease.
3. Filamentous Hemagglutinin (FHA): A surface protein that allows the bacterium to adhere to host cells and evade the immune response.
4. Fimbriae: Hair-like appendages on the surface of the bacterium that facilitate adherence to host cells.
5. Pertactin (PRN): A surface protein that also contributes to adherence and is a common component of acellular pertussis vaccines.
6. Dermonecrotic Toxin: A toxin that causes localized tissue damage and necrosis, contributing to the inflammation and symptoms of whooping cough.
7. Tracheal Cytotoxin: A toxin that damages ciliated epithelial cells in the respiratory tract, impairing mucociliary clearance and increasing susceptibility to infection.

These virulence factors work together to enable Bordetella pertussis to colonize the respiratory tract, evade the host immune response, and cause the symptoms of whooping cough.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Neuromuscular depolarizing agents are a type of muscle relaxant used in anesthesia and critical care medicine. These drugs work by causing depolarization of the post-synaptic membrane at the neuromuscular junction, which is the site where nerve impulses are transmitted to muscles. This results in the binding of the drug to the receptor and the activation of ion channels, leading to muscle contraction.

The most commonly used depolarizing agent is suxamethonium (also known as succinylcholine), which has a rapid onset and short duration of action. It is often used during rapid sequence intubation, where there is a need for immediate muscle relaxation to facilitate endotracheal intubation.

However, the use of depolarizing agents can also lead to several side effects, including increased potassium levels in the blood (hyperkalemia), muscle fasciculations, and an increase in intracranial and intraocular pressure. Therefore, these drugs should be used with caution and only under the close supervision of a trained healthcare provider.

Amylases are enzymes that break down complex carbohydrates, such as starch and glycogen, into simpler sugars like maltose, glucose, and maltotriose. There are several types of amylases found in various organisms, including humans.

In humans, amylases are produced by the pancreas and salivary glands. Pancreatic amylase is released into the small intestine where it helps to digest dietary carbohydrates. Salivary amylase, also known as alpha-amylase, is secreted into the mouth and begins breaking down starches in food during chewing.

Deficiency or absence of amylases can lead to difficulties in digesting carbohydrates and may cause symptoms such as bloating, diarrhea, and abdominal pain. Elevated levels of amylase in the blood may indicate conditions such as pancreatitis, pancreatic cancer, or other disorders affecting the pancreas.

Cholecystokinin (CCK) is a hormone that is produced in the duodenum (the first part of the small intestine) and in the brain. It is released into the bloodstream in response to food, particularly fatty foods, and plays several roles in the digestive process.

In the digestive system, CCK stimulates the contraction of the gallbladder, which releases bile into the small intestine to help digest fats. It also inhibits the release of acid from the stomach and slows down the movement of food through the intestines.

In the brain, CCK acts as a neurotransmitter and has been shown to have effects on appetite regulation, mood, and memory. It may play a role in the feeling of fullness or satiety after eating, and may also be involved in anxiety and panic disorders.

CCK is sometimes referred to as "gallbladder-stimulating hormone" or "pancreozymin," although these terms are less commonly used than "cholecystokinin."

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

Norepinephrine, also known as noradrenaline, is a neurotransmitter and a hormone that is primarily produced in the adrenal glands and is released into the bloodstream in response to stress or physical activity. It plays a crucial role in the "fight-or-flight" response by preparing the body for action through increasing heart rate, blood pressure, respiratory rate, and glucose availability.

As a neurotransmitter, norepinephrine is involved in regulating various functions of the nervous system, including attention, perception, motivation, and arousal. It also plays a role in modulating pain perception and responding to stressful or emotional situations.

In medical settings, norepinephrine is used as a vasopressor medication to treat hypotension (low blood pressure) that can occur during septic shock, anesthesia, or other critical illnesses. It works by constricting blood vessels and increasing heart rate, which helps to improve blood pressure and perfusion of vital organs.

Hexamethonium is defined as a ganglionic blocker, which is a type of medication that blocks the activity at the junction between two nerve cells (neurons) called the neurotransmitter receptor site. It is a non-depolarizing neuromuscular blocking agent, which means it works by binding to and inhibiting the action of the nicotinic acetylcholine receptors at the motor endplate, where the nerve meets the muscle.

Hexamethonium was historically used in anesthesia practice as a adjunct to provide muscle relaxation during surgical procedures. However, its use has largely been replaced by other neuromuscular blocking agents that have a faster onset and shorter duration of action. It is still used in research settings to study the autonomic nervous system and for the treatment of hypertensive emergencies in some cases.

It's important to note that the use of Hexamethonium requires careful monitoring and management, as it can have significant effects on cardiovascular function and other body systems.

The colon, also known as the large intestine, is a part of the digestive system in humans and other vertebrates. It is an organ that eliminates waste from the body and is located between the small intestine and the rectum. The main function of the colon is to absorb water and electrolytes from digested food, forming and storing feces until they are eliminated through the anus.

The colon is divided into several regions, including the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus. The walls of the colon contain a layer of muscle that helps to move waste material through the organ by a process called peristalsis.

The inner surface of the colon is lined with mucous membrane, which secretes mucus to lubricate the passage of feces. The colon also contains a large population of bacteria, known as the gut microbiota, which play an important role in digestion and immunity.

Cholinergic fibers are nerve cell extensions (neurons) that release the neurotransmitter acetylcholine at their synapses, which are the junctions where they transmit signals to other neurons or effector cells such as muscles and glands. These fibers are a part of the cholinergic system, which plays crucial roles in various physiological processes including learning and memory, attention, arousal, sleep, and muscle contraction.

Cholinergic fibers can be found in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS, cholinergic neurons are primarily located in the basal forebrain and brainstem, and their projections innervate various regions of the cerebral cortex, hippocampus, thalamus, and other brain areas. In the PNS, cholinergic fibers are responsible for activating skeletal muscles through neuromuscular junctions, as well as regulating functions in smooth muscles, cardiac muscles, and glands via the autonomic nervous system.

Dysfunction of the cholinergic system has been implicated in several neurological disorders, such as Alzheimer's disease, Parkinson's disease, and myasthenia gravis.

The pancreas is a glandular organ located in the abdomen, posterior to the stomach. It has both exocrine and endocrine functions. The exocrine portion of the pancreas consists of acinar cells that produce and secrete digestive enzymes into the duodenum via the pancreatic duct. These enzymes help in the breakdown of proteins, carbohydrates, and fats in food.

The endocrine portion of the pancreas consists of clusters of cells called islets of Langerhans, which include alpha, beta, delta, and F cells. These cells produce and secrete hormones directly into the bloodstream, including insulin, glucagon, somatostatin, and pancreatic polypeptide. Insulin and glucagon are critical regulators of blood sugar levels, with insulin promoting glucose uptake and storage in tissues and glucagon stimulating glycogenolysis and gluconeogenesis to raise blood glucose when it is low.

Thapsigargin is not a medical term per se, but it is a chemical compound that has been studied in the field of medicine and biology. Thapsigargin is a substance that is derived from the plant Thapsia garganica, also known as the "deadly carrot." It is a powerful inhibitor of the sarcoendoplasmic reticulum calcium ATPase (SERCA) pump, which is responsible for maintaining calcium homeostasis within cells.

Thapsigargin has been studied for its potential use in cancer therapy due to its ability to induce cell death in certain types of cancer cells. However, its use as a therapeutic agent is still being investigated and is not yet approved for medical use. It should be noted that thapsigargin can also have toxic effects on normal cells, so its therapeutic use must be carefully studied and optimized to minimize harm to healthy tissues.

Inositol is not considered a true "vitamin" because it can be created by the body from glucose. However, it is an important nutrient and is sometimes referred to as vitamin B8. It is a type of sugar alcohol that is found in both animals and plants. Inositol is involved in various biological processes, including:

1. Signal transduction: Inositol phospholipids are key components of cell membranes and play a crucial role in intracellular signaling pathways. They act as secondary messengers in response to hormones, neurotransmitters, and growth factors.
2. Insulin sensitivity: Inositol and its derivatives, such as myo-inositol and D-chiro-inositol, are involved in insulin signal transduction. Abnormalities in inositol metabolism have been linked to insulin resistance and conditions like polycystic ovary syndrome (PCOS).
3. Cerebral and ocular functions: Inositol is essential for the proper functioning of neurons and has been implicated in various neurological and psychiatric disorders, such as depression, anxiety, and bipolar disorder. It also plays a role in maintaining eye health.
4. Lipid metabolism: Inositol participates in the breakdown and transport of fats within the body.
5. Gene expression: Inositol and its derivatives are involved in regulating gene expression through epigenetic modifications.

Inositol can be found in various foods, including fruits, beans, grains, nuts, and vegetables. It is also available as a dietary supplement for those who wish to increase their intake.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

GTP-binding proteins, also known as G proteins, are a family of molecular switches present in many organisms, including humans. They play a crucial role in signal transduction pathways, particularly those involved in cellular responses to external stimuli such as hormones, neurotransmitters, and sensory signals like light and odorants.

G proteins are composed of three subunits: α, β, and γ. The α-subunit binds GTP (guanosine triphosphate) and acts as the active component of the complex. When a G protein-coupled receptor (GPCR) is activated by an external signal, it triggers a conformational change in the associated G protein, allowing the α-subunit to exchange GDP (guanosine diphosphate) for GTP. This activation leads to dissociation of the G protein complex into the GTP-bound α-subunit and the βγ-subunit pair. Both the α-GTP and βγ subunits can then interact with downstream effectors, such as enzymes or ion channels, to propagate and amplify the signal within the cell.

The intrinsic GTPase activity of the α-subunit eventually hydrolyzes the bound GTP to GDP, which leads to re-association of the α and βγ subunits and termination of the signal. This cycle of activation and inactivation makes G proteins versatile signaling elements that can respond quickly and precisely to changing environmental conditions.

Defects in G protein-mediated signaling pathways have been implicated in various diseases, including cancer, neurological disorders, and cardiovascular diseases. Therefore, understanding the function and regulation of GTP-binding proteins is essential for developing targeted therapeutic strategies.

  • Carbachol, also known as carbamylcholine and sold under the brand name Miostat among others, is a cholinomimetic drug that binds and activates acetylcholine receptors. (wikipedia.org)
  • carbachol (Miostat) or pilocarpine (Isopto Carpine, Salagen). (nih.gov)
  • and eye drops such as acetylcholine chloride (Miochol E) and carbachol (Miostat, Isopto Carbachol). (medlineplus.gov)
  • Concurrent stimulation with carbachol and morphine promoted MOP receptor internalization, desensitization and down-regulation and this facilitation was not dependent on PKC activation. (gla.ac.uk)
  • The exact mechanism by which carbachol lowers intraocular pressure is not precisely known. (nih.gov)
  • In addition, carbachol, 0.01%, is an effective hypotensive drug that lowers intraocular pressure (IOP) during the crucial 24-hour period after surgery. (aao.org)
  • CARBASTAT ® (Carbachol Intraocular Solution, USP) 0.01% is a sterile balanced salt solution of carbachol for intraocular injection. (nih.gov)
  • In addition, Carbastat ® (Carbachol Intraocular Solution USP) reduces the intensity of intraocular pressure elevation in the first 24 hours after cataract surgery. (nih.gov)
  • Use of carbachol, as well as all other muscarinic receptor agonists, is contraindicated in patients with asthma, coronary insufficiency, gastroduodenal ulcers, and incontinence. (wikipedia.org)
  • Because there is a direct relationship between phosphatidylinositol (PI) metabolism and airway smooth muscle contraction induced by muscarinic agonists, the authors examined the effects of carbachol (CCh), norepinephrine (NE), and hypocapnia on PI turnover in the airway smooth muscle. (silverchair.com)
  • IP3-mediated Ca2+ release also was observed in the presence of the metabotropic agonists t-ACPD and carbachol when backpropagating spikes were generated. (nih.gov)
  • Carbachol is primarily used in the treatment of glaucoma, but it is also used during ophthalmic surgery. (wikipedia.org)
  • No information is available on the use of carbachol ophthalmic drops during breastfeeding. (nih.gov)
  • Carbachol is a prescription medication used to constrict the pupil and lower eye pressure during surgery as well as reduce the pressure elevation in the eye after cataract surgery. (rxwiki.com)
  • Response was measured as a percent of maximal carbachol contraction. (cdc.gov)
  • Carbachol is not easily metabolized by cholinesterase, it has a 2 to 5 minute onset of action and its duration of action is 4 to 8 hours with topical administration and 24 hours for intraocular administration. (wikipedia.org)
  • Carbachol is a potent cholinergic (parasympathomimetic) agent which produces constriction of the iris and ciliary body resulting in reduction in intraocular pressure. (nih.gov)
  • Intraocular carbachol 0.01% should be used with caution in patients with acute cardiac failure, bronchial asthma, peptic ulcer, hyperthyroidism, G.I. spasm, urinary tract obstruction and Parkinson's disease. (nih.gov)
  • To evaluate safety and efficacy, Dr Abdelkader compared the combination of carbachol and brimonidine with placebo in two groups of patients with emmetropic presbyopia. (medscape.com)
  • In the first group, the nondominant eye of 30 patients was treated with a combination of 2.25% carbachol plus 0.2% brimonidine, and of 18 patients was treated with placebo. (medscape.com)
  • In the second group, 10 patients received 3% carbachol, 0.2% brimonidine, a combination of the two, or placebo. (medscape.com)
  • From these results, Dr Abdelkader determined that the optimal formula is a combination of carbachol and brimonidine. (medscape.com)
  • The people who received the carbachol and brimonidine combination said they liked it and would use it as a therapy if it were available. (medscape.com)
  • Since carbachol is poorly absorbed through topical administration, benzalkonium chloride is mixed in to promote absorption. (wikipedia.org)
  • A recent review indicates that carbachol is a strong promoter of ICC activity, which is mediated through the calcium-activated chloride channel, anoctamin 1. (wikipedia.org)
  • Results The cumulative chloride secretory response of ΔI sc,carbachol , ΔI sc,cAMP/forskolin and ΔI sc,histamine was the best diagnostic ICM parameter (cut-off 34 μA/cm 2 between patients with known PS-CF and controls), differentiating patients with questionable CF into PS-CF (n=6) and 'CF unlikely' (n=55) groups. (bmj.com)
  • Carbachol is a parasympathomimetic that stimulates both muscarinic and nicotinic receptors. (wikipedia.org)
  • Carbachol is also available as an injection and is given into the eye during the eye procedure. (rxwiki.com)
  • Notably, retinas from rats treated with a single subcutaneous injection of 100 mg/kg fenthion showed decreases in carbachol-stimulated release of inositol phosphate, an indicator of cholinergically-mediated intracellular second messenger systems. (epa.gov)
  • The cholinergic agonist carbachol, after 24 h in vitro, increased the length of the axon, without affecting the length of minor neurites. (nih.gov)
  • Carbachol eyedrops are used to decrease the pressure in the eye for people with glaucoma. (wikipedia.org)
  • Carbachol is also used to treat glaucoma. (rxwiki.com)
  • Effects of Helicobacter pylori on histamine and carbachol stimulated acid secretion by human parietal cells. (bmj.com)
  • Bronchospasms occur in instances of high levels of carbachol or potassium, which are able to cause tracheal tissue contractions by simultaneously opening L-type calcium channels and stimulating muscarinic receptors. (discovermagazine.com)
  • The effect of carbachol was mediated by the M(1) subtype of muscarinic receptors. (nih.gov)
  • C7/3-phth also produced supra-additive inhibition of the negative inotropic effects of carbachol when combined with NMS. (aspetjournals.org)
  • 8. Carbachol alleviates myocardial injury in septic rats through PI3K/AKT signaling pathway. (nih.gov)
  • Moreover, cardamom extracts were observed to relax carbachol- and potassium-induced contractions in tracheal tissues [2], effectively relieving bronchospasms in asthma attacks. (discovermagazine.com)
  • carbachol and potassium interaction with these signaling pathways leads to airway constrictions. (discovermagazine.com)
  • In the study, cardamom showed inhibitory effects against carbachol and potassium, enabling relaxation of the contracted tissues. (discovermagazine.com)
  • Side effects such as flushing, sweating, epigastric distress, abdominal cramps, tightness in urinary bladder, and headache have been reported with topical or systemic application of carbachol. (nih.gov)
  • Serious side effects have been reported with carbachol. (rxwiki.com)
  • This is not a complete list of carbachol side effects. (rxwiki.com)
  • Effects of in vivo ischemia on contractile responses of rabbit bladder to field stimulation, carbachol, ATP and KCl. (upstate.edu)
  • The main differences between waves in neocortical neurons and in previously described hippocampal pyramidal neurons were, (a) Ca2+ waves in L5 neurons could be evoked further out along the main shaft, (b) Ca2+ waves extended slightly further out into the oblique dendrites and (c) higher concentrations of bath-applied t-ACPD and carbachol were required to generate Ca2+ release events by backpropagating action potentials. (nih.gov)
  • Carbachol-induced axonal growth was also observed in pyramidal neurons from the neocortex but not in granule neurons from the cerebellum. (nih.gov)
  • Carbachol constricts the pupil during medical procedures. (rxwiki.com)
  • During either generalized forebrain activation or selective thalamic activation caused by carbachol infusion in the VPM, the responses to AWs enhance so that VPM receptive fields become much larger. (nih.gov)
  • In addition, down-regulation of ERK1/2 with small interfering RNA abolished the neuritogenic effect of carbachol. (nih.gov)
  • Patients who received carbachol monotherapy experienced a drop to a little above 5 in the first hour, which rose to just above 7 at 8 hours. (medscape.com)
  • IL instilled mebeverine (1 × 10 -6 M) inhibited the carbachol dose response of the ileal and colonic segments more than an equivalent dose of mebeverine infused IA. (annals.edu.sg)
  • A "mild burning sensation" was reported by some subjects in each of the groups, including the placebo group, but most frequently in the carbachol monotherapy group. (medscape.com)
  • Carbachol belongs to a group of medications called cholinergics. (rxwiki.com)
  • Carbachol can also be used to stimulate bladder emptying to treat the condition of underactive bladder. (wikipedia.org)
  • Carbachol elicits this REM sleep-like state via activation of postsynaptic muscarinic cholinergic receptors (mAChRs). (wikipedia.org)
  • Inward cationic current was activated by the application of 50 pM carbachol (I(CCh)) at a holding potential of -60 mV with the same CsCl-rich solution in both pipette and bath. (ewha.ac.kr)

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