4-Aminopyridine: One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.Aminopyridines: Pyridines substituted in any position with an amino group. May be hydrogenated, but must retain at least one double bond.Potassium Channel Blockers: A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.Tetraethylammonium: A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)Tetraethylammonium CompoundsPotassium Channels: Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.Membrane Potentials: 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).Potassium Channels, Voltage-Gated: Potassium channel whose permeability to ions is extremely sensitive to the transmembrane potential difference. The opening of these channels is induced by the membrane depolarization of the ACTION POTENTIAL.Potassium: 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.Charybdotoxin: A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Delayed Rectifier Potassium Channels: A group of slow opening and closing voltage-gated potassium channels. Because of their delayed activation kinetics they play an important role in controlling ACTION POTENTIAL duration.Kv1.5 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that conducts a delayed rectifier current. It contributes to ACTION POTENTIAL repolarization of MYOCYTES in HEART ATRIA.Elapid Venoms: Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.Barium Compounds: Inorganic compounds that contain barium as an integral part of the molecule.Neuromuscular Depolarizing Agents: 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.Apamin: A highly neurotoxic polypeptide from the venom of the honey bee (Apis mellifera). It consists of 18 amino acids with two disulfide bridges and causes hyperexcitability resulting in convulsions and respiratory paralysis.Barium: An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.Tetrodotoxin: An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Calcium: 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.Cesium: A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.Glyburide: An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.Quinidine: An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.Potassium Channels, Calcium-Activated: Potassium channels whose activation is dependent on intracellular calcium concentrations.Kv1.4 Potassium Channel: A fast inactivating subtype of shaker potassium channels that contains two inactivation domains at its N terminus.Scorpion Venoms: Venoms from animals of the order Scorpionida of the class Arachnida. They contain neuro- and hemotoxins, enzymes, and various other factors that may release acetylcholine and catecholamines from nerve endings. Of the several protein toxins that have been characterized, most are immunogenic.Guinea Pigs: 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.Ion Channels: Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.Shaw Potassium Channels: A shaker subfamily that is prominently expressed in NEURONS and are necessary for high-frequency, repetitive firing of ACTION POTENTIALS.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Rats, Sprague-Dawley: 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.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Ion Channel Gating: The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.Calcium Channel Blockers: A class of drugs that act by selective inhibition of calcium influx through cellular membranes.Quinine: An alkaloid derived from the bark of the cinchona tree. It is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. Quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. It was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. Quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. The mechanisms of its antimalarial effects are not well understood.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Kv1.1 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is commonly mutated in human episodic ATAXIA and MYOKYMIA.Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Shab Potassium Channels: A subfamily of shaker potassium channels that shares homology with its founding member, Shab protein, Drosophila. They regulate delayed rectifier currents in the NERVOUS SYSTEM of DROSOPHILA and in the SKELETAL MUSCLE and HEART of VERTEBRATES.Kv1.2 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS.Endothelium-Dependent Relaxing Factors: Paracrine substances produced by the VASCULAR ENDOTHELIUM with VASCULAR SMOOTH MUSCLE relaxation (VASODILATION) activities. Several factors have been identified, including NITRIC OXIDE and PROSTACYCLIN.Synaptic Transmission: The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.Convulsants: Substances that act in the brain stem or spinal cord to produce tonic or clonic convulsions, often by removing normal inhibitory tone. They were formerly used to stimulate respiration or as antidotes to barbiturate overdose. They are now most commonly used as experimental tools.Pyridostigmine Bromide: A cholinesterase inhibitor with a slightly longer duration of action than NEOSTIGMINE. It is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants.Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.Microelectrodes: Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)Shaker Superfamily of Potassium Channels: Voltage-gated potassium channels whose primary subunits contain six transmembrane segments and form tetramers to create a pore with a voltage sensor. They are related to their founding member, shaker protein, Drosophila.Tubocurarine: A neuromuscular blocker and active ingredient in CURARE; plant based alkaloid of Menispermaceae.Shal Potassium Channels: A shaker subfamily of potassium channels that participate in transient outward potassium currents by activating at subthreshold MEMBRANE POTENTIALS, inactivating rapidly, and recovering from inactivation quickly.Acetylcholine: 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.Vasodilation: The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.Cromakalim: A potassium-channel opening vasodilator that has been investigated in the management of hypertension. It has also been tried in patients with asthma. (Martindale, The Extra Pharmacopoeia, 30th ed, p352)Muscle Relaxation: That phase of a muscle twitch during which a muscle returns to a resting position.Procaine: A local anesthetic of the ester type that has a slow onset and a short duration of action. It is mainly used for infiltration anesthesia, peripheral nerve block, and spinal block. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1016).QuinoxalinesPulmonary Stretch Receptors: Stretch receptors found in the bronchi and bronchioles. Pulmonary stretch receptors are sensors for a reflex which stops inspiration. In humans, the reflex is protective and is probably not activated during normal respiration.Cadmium: An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.Evoked Potentials: Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.Large-Conductance Calcium-Activated Potassium Channels: A major class of calcium activated potassium channels whose members are voltage-dependent. MaxiK channels are activated by either membrane depolarization or an increase in intracellular Ca(2+). They are key regulators of calcium and electrical signaling in a variety of tissues.Neuromuscular Junction: The synapse between a neuron and a muscle.Potassium Channels, Tandem Pore Domain: Potassium channels that contain two pores in tandem. They are responsible for baseline or leak currents and may be the most numerous of all K channels.Pinacidil: A guanidine that opens POTASSIUM CHANNELS producing direct peripheral vasodilatation of the ARTERIOLES. It reduces BLOOD PRESSURE and peripheral resistance and produces fluid retention. (Martindale The Extra Pharmacopoeia, 31st ed)Pyramidal Cells: Projection neurons in the CEREBRAL CORTEX and the HIPPOCAMPUS. Pyramidal cells have a pyramid-shaped soma with the apex and an apical dendrite pointed toward the pial surface and other dendrites and an axon emerging from the base. The axons may have local collaterals but also project outside their cortical region.Polymyxins: Basic lipopeptide antibiotic group obtained from Bacillus polymyxa. They affect the cell membrane by detergent action and may cause neuromuscular and kidney damage. At least eleven different members of the polymyxin group have been identified, each designated by a letter.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Pulmonary Artery: The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Calcium Channels: Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.Kinetics: The rate dynamics in chemical or physical systems.Potassium Chloride: 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.Nerve Endings: Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.Verapamil: A calcium channel blocker that is a class IV anti-arrhythmia agent.Heart Ventricles: The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.FMRFamide: A molluscan neuroactive peptide which induces a fast excitatory depolarizing response due to direct activation of amiloride-sensitive SODIUM CHANNELS. (From Nature 1995; 378(6558): 730-3)Muscle Contraction: 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.Nifedipine: A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.Vasoconstriction: The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.Heart: The hollow, muscular organ that maintains the circulation of the blood.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Seizures: Clinical or subclinical disturbances of cortical function due to a sudden, abnormal, excessive, and disorganized discharge of brain cells. Clinical manifestations include abnormal motor, sensory and psychic phenomena. Recurrent seizures are usually referred to as EPILEPSY or "seizure disorder."Ventricular Function: The hemodynamic and electrophysiological action of the HEART VENTRICLES.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Neurotransmitter Agents: Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.Carbenoxolone: An agent derived from licorice root. It is used for the treatment of digestive tract ulcers, especially in the stomach. Antidiuretic side effects are frequent, but otherwise the drug is low in toxicity.Epilepsy: A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)Excitatory Amino Acid Antagonists: Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.OxadiazolesBicuculline: An isoquinoline alkaloid obtained from Dicentra cucullaria and other plants. It is a competitive antagonist for GABA-A receptors.Carbohydrate Conformation: The characteristic 3-dimensional shape of a carbohydrate.Muscle, Smooth: 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)

Characterization of K+ currents underlying pacemaker potentials of fish gonadotropin-releasing hormone cells. (1/1089)

Endogenous pacemaker activities are important for the putative neuromodulator functions of the gonadotropin-releasing hormone (GnRH)-immunoreactive terminal nerve (TN) cells. We analyzed several types of voltage-dependent K+ currents to investigate the ionic mechanisms underlying the repolarizing phase of pacemaker potentials of TN-GnRH cells by using the whole brain in vitro preparation of fish (dwarf gourami, Colisa lalia). TN-GnRH cells have at least four types of voltage-dependent K+ currents: 1) 4-aminopyridine (4AP)-sensitive K+ current, 2) tetraethylammonium (TEA)-sensitive K+ current, and 3) and 4) two types of TEA- and 4AP-resistant K+ currents. A transient, low-threshold K+ current, which was 4AP sensitive and showed significant steady-state inactivation in the physiological membrane potential range (-40 to -60 mV), was evoked from a holding potential of -100 mV. This current thus cannot contribute to the repolarizing phase of pacemaker potentials. TEA-sensitive K+ current evoked from a holding potential of -100 mV was slowly activating, long lasting, and showed comparatively low threshold of activation. This current was only partially inactivated at steady state of -60 to -40 mV, which is equivalent to the resting membrane potential. TEA- and 4AP-resistant sustained K+ currents were evoked from a holding potential of -100 mV and were suggested to consist of two types, based on the analysis of activation curves. From the inactivation and activation curves, it was suggested that one of them with low threshold of activation may be partly involved in the repolarizing phase of pacemaker potentials. Bath application of TEA together with tetrodotoxin reversibly blocked the pacemaker potentials in current-clamp recordings. We conclude that the TEA-sensitive K+ current is the most likely candidate that contributes to the repolarizing phase of the pacemaker potentials of TN-GnRH cells.  (+info)

Presynaptic action of adenosine on a 4-aminopyridine-sensitive current in the rat carotid body. (2/1089)

1. Plasma adenosine concentration increases during hypoxia to a level that excites carotid body chemoreceptors by an undetermined mechanism. We have examined this further by determining the electrophysiological responses to exogenous adenosine of sinus nerve chemoafferents in vitro and of whole-cell currents in isolated type I cells. 2. Steady-state, single-fibre chemoafferent discharge was increased approximately 5-fold above basal levels by 100 microM adenosine. This adenosine-stimulated discharge was reversibly and increasingly reduced by methoxyverapamil (D600, 100 microM), by application of nickel chloride (Ni2+, 2 mM) and by removal of extracellular Ca2+. These effects strongly suggest a presynaptic, excitatory action of adenosine on type I cells of the carotid body. 3. Adenosine decreased whole-cell outward currents at membrane potentials above -40 mV in isolated type I cells recorded during superfusion with bicarbonate-buffered saline solution at 34-36 C. This effect was reversible and concentration dependent with a maximal effect at 10 microM. 4. The degree of current inhibition induced by 10 microM adenosine was voltage independent (45.39 +/- 2. 55 % (mean +/- s.e.m.) between -40 and +30 mV) and largely ( approximately 75 %), but not entirely, Ca2+ independent. 4-Aminopyridine (4-AP, 5 mM) decreased the amplitude of the control outward current by 80.60 +/- 3.67 % and abolished the effect of adenosine. 5. Adenosine was without effect upon currents near the resting membrane potential of approximately -55 mV and did not induce depolarization in current-clamp experiments. 6. We conclude that adenosine acts to inhibit a 4-AP-sensitive current in isolated type I cells of the rat carotid body and suggest that this mechanism contributes to the chemoexcitatory effect of adenosine in the whole carotid body.  (+info)

Contribution of delayed rectifier potassium currents to the electrical activity of murine colonic smooth muscle. (3/1089)

1. We used intracellular microelectrodes to record the membrane potential (Vm) of intact murine colonic smooth muscle. Electrical activity consisted of spike complexes separated by quiescent periods (Vm approximately -60 mV). The spike complexes consisted of about a dozen action potentials of approximately 30 mV amplitude. Tetraethylammonium (TEA, 1-10 mM) had little effect on the quiescent periods but increased the amplitude of the action potential spikes. 4-Aminopyridine (4-AP, >= 5 mM) caused continuous spiking. 2. Voltage clamp of isolated myocytes identified delayed rectifier K+ currents that activated rapidly (time to half-maximum current, 11.5 ms at 0 mV) and inactivated in two phases (tauf = 96 ms, taus = 1.5 s at 0 mV). The half-activation voltage of the permeability was -27 mV, with significant activation at -50 mV. 3. TEA (10 mM) reduced the outward current at potentials positive to 0 mV. 4-AP (5 mM) reduced the early current but increased outward current at later times (100-500 ms) consistent with block of resting channels relieved by depolarization. 4-AP inhibited outward current at potentials negative to -20 mV, potentials where TEA had no effect. 4. Qualitative PCR amplification of mRNA identified transcripts encoding delayed rectifier K+ channel subunits Kv1.6, Kv4.1, Kv4.2, Kv4.3 and the Kvbeta1.1 subunit in murine colon myocytes. mRNA encoding Kv 1.4 was not detected. 5. We find that TEA-sensitive delayed rectifier currents are important determinants of action potential amplitude but not rhythmicity. Delayed rectifier currents sensitive to 4-AP are important determinants of rhythmicity but not action potential amplitude.  (+info)

Calcium responses induced by acetylcholine in submucosal arterioles of the guinea-pig small intestine. (4/1089)

1. Calcium responses induced by brief stimulation with acetylcholine (ACh) were assessed from the fluorescence changes in fura-2 loaded submucosal arterioles of the guinea-pig small intestine. 2. Initially, 1-1.5 h after loading with fura-2 (fresh tissues), ACh increased [Ca2+]i in a concentration-dependent manner. This response diminished with time, and finally disappeared in 2-3 h (old tissues). 3. Ba2+ elevated [Ca2+]i to a similar extent in both fresh and old tissues. ACh further increased the Ba2+-elevated [Ca2+]i in fresh tissues, but reduced it in old tissues. Responses were not affected by either indomethacin or nitroarginine. 4. In fresh mesenteric arteries, mechanical removal of endothelial cells abolished the ACh-induced increase in [Ca2+]i, with no alteration of [Ca2+]i at rest and during elevation with Ba2+. 5. In the presence of indomethacin and nitroarginine, high-K+ solution elevated [Ca2+]i in both fresh and old tissues. Subsequent addition of ACh further increased [Ca2+]i in fresh tissues without changing it in old tissues. 6. Proadifen, an inhibitor of the enzyme cytochrome P450 mono-oxygenase, inhibited the ACh-induced changes in [Ca2+]i in both fresh and Ba2+-stimulated old tissues. It also inhibited the ACh-induced hyperpolarization. 7. In fresh tissues, the ACh-induced Ca2+ response was not changed by apamin, charybdotoxin (CTX), 4-aminopyridine (4-AP) or glibenclamide. In old tissues in which [Ca2+]i had previously been elevated with Ba2+, the ACh-induced Ca2+ response was inhibited by CTX but not by apamin, 4-AP or glibenclamide. 8. It is concluded that in submucosal arterioles, ACh elevates endothelial [Ca2+]i and reduces muscular [Ca2+]i, probably through the hyperpolarization of endothelial or smooth muscle membrane by activating CTX-sensitive K+ channels.  (+info)

Identification and characterization of multiple subtypes of muscarinic acetylcholine receptors and their physiological functions in canine hearts. (5/1089)

M2 receptors have long been believed to be the only functional subtype of muscarinic acetylcholine receptor (mAChR) in the heart, although recent studies have provided evidence for the presence of other subtypes. We performed a detailed study to clarify this issue. In the presence of tetramethylammonium (1 microM to 10 mM), a novel K+ current with both delayed rectifying and inward rectifying properties (IKTMA) was activated in single canine atrial myocytes. 4-Aminopyridine (0.05-2 mM) also induced a K+ current (IK4AP) with characteristics similar to but distinct from those of IKTMA. Both IKTMA and IK4AP were abolished by 1 microM atropine. IK4AP, but not IKTMA, was minimized by treatment with pertussis toxin. IKTMA was markedly decreased by 4-diphenylacetoxy-N-methylpiperidine methiodide (a selective antagonist for M3 subtype) but was not altered by pirenzepine (for M1), methoctramine (for M2), and tropicamide (for M4). Tropicamide substantially reduced IK4AP, but the antagonists for other mAChR subtypes had no effects on IK4AP. By comparison, IKACh (ACh-induced K+ current) was significantly depressed by methoctramine but was unaltered by other antagonists. Results from displacement binding of [methyl-3H]N-scopolamine methyl chloride with pirenzepine, methoctramine, 4-diphenylacetoxy-N-methylpiperidine methiodide, or tropicamide revealed the coexistence of multiple mAChR subtypes in canine atrium. Cloning of cDNA fragments and detection of mRNAs coding for M2, M3, and M4 provided further supporting evidence. Our results suggest that 1) multiple subtypes of mAChRs (M2/M3/M4) coexist in the dog heart and 2) different subtypes of mAChRs are coupled to different K+ channels. Our findings represent the first functional evidence for the physiological role of cardiac M3 and M4 receptors.  (+info)

Transient potassium currents regulate the discharge patterns of dorsal cochlear nucleus pyramidal cells. (6/1089)

Pyramidal cells in the dorsal cochlear nucleus (DCN) show three distinct temporal discharge patterns in response to sound: "pauser," "buildup," and "chopper." Similar discharge patterns are seen in vitro and depend on the voltage from which the cell is depolarized. It has been proposed that an inactivating A-type K+ current (IKI) might play a critical role in generating the three different patterns. In this study we examined the characteristics of transient currents in DCN pyramidal cells to evaluate this hypothesis. Morphologically identified pyramidal cells in rat brain slices (P11-P17) exhibited the three voltage-dependent discharge patterns. Two inactivating currents were present in outside-out patches from pyramidal cells: a rapidly inactivating (IKIF, tau approximately 11 msec) current insensitive to block by tetraethylammonium (TEA) and variably blocked by 4-aminopyridine (4-AP) with half-inactivation near -85 mV, and a slowly inactivating TEA- and 4-AP-sensitive current (IKIS, tau approximately 145 msec) with half-inactivation near -35 mV. Recovery from inactivation at 34 degrees C was described by a single exponential with a time constant of 10-30 msec, similar to the rate at which first spike latency increases with the duration of a hyperpolarizing prepulse. Acutely isolated cells also possessed a rapidly activating (<1 msec at 22 degrees C) transient current that activated near -45 mV and showed half-inactivation near -80 mV. A model demonstrated that the deinactivation of IKIF was correlated with the discharge patterns. Overall, the properties of the fast inactivating K+ current were consistent with their proposed role in shaping the discharge pattern of DCN pyramidal cells.  (+info)

On the mechanism of histaminergic inhibition of glutamate release in the rat dentate gyrus. (7/1089)

1. Histaminergic depression of excitatory synaptic transmission in the rat dentate gyrus was investigated using extracellular and whole-cell patch-clamp recording techniques in vitro. 2. Application of histamine (10 microM, 5 min) depressed synaptic transmission in the dentate gyrus for 1 h. This depression was blocked by the selective antagonist of histamine H3 receptors, thioperamide (10 microM). 3. The magnitude of the depression caused by histamine was inversely related to the extracellular Ca2+ concentration. Application of the N-type calcium channel blocker omega-conotoxin (0. 5 or 1 microM) or the P/Q-type calcium channel blocker omega-agatoxin (800 nM) did not prevent depression of synaptic transmission by histamine. 4. The potassium channel blocker 4-aminopyridine (4-AP, 100 microM) enhanced synaptic transmission and reduced the depressant effect of histamine (10 microM). 4-AP reduced the effect of histamine more in 2 mM extracellular calcium than in 4 mM extracellular calcium. 5. Histamine (10 microM) did not affect the amplitude of miniature excitatory postsynaptic currents (mEPSCs) and had only a small effect on their frequency. 6. Histaminergic depression was not blocked by an inhibitor of serine/threonine protein kinases, H7 (100 microM), or by an inhibitor of tyrosine kinases, Lavendustin A (10 microM). 7. Application of adenosine (20 microM) or the adenosine A1 agonist N6-cyclopentyladenosine (CPA, 0.3 microM) completely occluded the effect of histamine (10 microM). 8. We conclude that histamine, acting on histamine H3 receptors, inhibits glutamate release by inhibiting presynaptic calcium entry, via a direct G-protein-mediated inhibition of multiple calcium channels. Histamine H3 receptors and adenosine A1 receptors act upon a common final effector to cause presynaptic inhibition.  (+info)

The cAMP transduction cascade mediates the PGE2-induced inhibition of potassium currents in rat sensory neurones. (8/1089)

1. The role of the cyclic AMP (cAMP) transduction cascade in mediating the prostaglandin E2 (PGE2)-induced decrease in potassium current (IK) was investigated in isolated embryonic rat sensory neurones using the whole-cell patch-clamp recording technique. 2. Exposure to 100 microM chlorophenylthio-adenosine cyclic 3', 5'-monophosphate (cpt-cAMP) or 1 microM PGE2 caused a slow suppression of the whole-cell IK by 34 and 36 %, respectively (measured after 20 min), without a shift in the voltage dependence of activation for this current. Neither of these agents altered the shape of the voltage-dependent inactivation curve indicating that the suppression of IK did not result from alterations in the inactivation properties. 3. To determine whether the PGE2-mediated suppression of IK depended on activation of the cAMP pathway, cells were exposed to this prostanoid in the presence of the protein kinase A (PKA) inhibitor, PKI. The PGE2-induced suppression of IK was prevented by PKI. In the absence of PGE2, PKI had no significant effect on the magnitude of IK. 4. Results obtained from protocols using different conditioning prepulse voltages indicated that the extent of cpt-cAMP- and PGE2-mediated suppression of IK was independent of the prepulse voltage. The subtraction of control and treated currents revealed that the cpt-cAMP- and PGE2-sensitive currents exhibited little time-dependent inactivation. Taken together, these results suggest that the modulated currents may be delayed rectifier-like IK. 5. Exposure to the inhibitors of IK, tetraethylammonium (TEA) or 4-aminopyridine (4-AP), reduced the control current elicited by a voltage step to +60 mV by 40-50 %. In the presence of 10 mM TEA, treatment with cpt-cAMP did not result in any further inhibition of IK. In contrast, cpt-cAMP reduced IK by an additional 25-30 % in the presence of 1 mM 4-AP. This effect was independent of the conditioning prepulse voltage. 6. These results establish that PGE2 inhibits an outward IK in sensory neurones via activation of PKA and are consistent with the idea that the PGE2-mediated sensitization of sensory neurones results, in part, from an inhibition of delayed rectifier-like IK.  (+info)

Looking for 4-aminopyridine? Find out information about 4-aminopyridine. C5H6N2 White crystals with a melting point of 158.9°C; soluble in water; used as a repellent for birds. Abbreviated 4-AP Explanation of 4-aminopyridine
4-aminopyridine CHEMICAL name: 4-aminopyridine TRADE name(S): Avitrol (56) FORMULATION(S): Grain baits: .5%, 1.0%, 3.0%. Powder concentrate: 25%, 50% (56). 25% concentrate, 50% powder mix. Various baits depending upon species to be controlled. Such baits as grain, corn and bread have proven effective (8c). TYPE: Avi-repellent BASIC PRODUCER(S): Avitrol Corp. 320 S. Boston, Suite 514 Tulsa, OK 74130 STATUS: Restricted use PRINCIPAL USES: EPA registered for control of crows, pigeons, grackles, starlings, sparrows, cowbirds, gulls, and blackbirds in and around structures and agriculture (sunflowers, field corn, sweet corn). Causes individual members of a flock of birds to utter vocal and physical distress which acts as an area repellency to the remainder of the flock (56). To drive birds from cattle feed lots, field corn, wheat, sorghum, sunflowers, agricultural areas, peanuts, pecans, grain, processing plants, air-ports, warehouse premises, public buildings and similar structures (8c). I. EFFICACY ...
This study provides novel information concerning the state-dependence of block by 4-AP and molecular identity of vascular KDR. We provide the first evidence that vascular KDR of RPV are inhibited by 4-AP via an open-state blocking mechanism. The inhibition by 4-AP was associated with a positive shift in the voltage dependence of steady-state activation. Kv1.2 and Kv1.5 cloned from the RPV were used to verify that our approach for determination of the mechanism of 4-AP block of RPV KDR would yield data consistent with previous reports concerning the cloned channels.14,17-20 We found that RPV Kv1.2 and Kv1.5 displayed evidence of open-state block consistent with previous findings,14,17-20 but we made the novel observation that 4-AP has disparate effects on the steady-state activation of homotetrameric channels composed of these subunits. Kv1.2 but not Kv1.5 channels displayed a positive shift in voltage-dependence of activation similar to that observed during 4-AP inhibition of RPV KDR. RPV KDR ...
[107 Pages Report] Check for Discount on Global 2-Aminopyridine Market Professional Survey Report 2016 report by QYResearch Group. This report Mainly covers the following product types The segment...
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Hartman, JAR; Kammier, AL; Spracklin, RJ; Pearson, WH; Combariza, MY; and Vachet, RW, "A comparison of the gas, solution, and solid state coordination environments for the Cu(II) complexes of a series of linear aminopyridine ligands with varying ratios of 5-and 6-membered chelate rings" (2004). INORGANICA CHIMICA ACTA. 1124 ...
Ketoconazole is effective only against fungal or yeast organisms. These fungi are the ones that cause skin infections (dermatophytes) commonly known as ringworm and toenail infections. However, the drug is also effective for some of the more serious fungal infections, such as blastomycosis, coccidoidomycosis and cryptococcosis. These infections can affect the skin, lymph nodes, eyes, bone and respiratory tract (lungs ...
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Hi all, just wanted to let people know about this stuff. I know I would of wanted to know about this earlier. A few months ago I came accross the study Acordia are doing on a substance called 4-Aminopyridine (ie ...
0055]The matrix in which the aminopyridine is homogeneously dispersed provides a sustained release of the aminopyridine into the plasma of the patient. Polymeric matrices suitable for controlling the release rate of aminopyridines for use in the pharmaceutical compositions of the present invention include hydrophilic polymers; hydrophobic polymers or mixtures of hydrophilic and/or hydrophobic polymers that are capable of forming sustained-release dosage formulation in combination with an aminopyridine. Such matrices are also capable of preventing degradation and loss of the aminopyridine from the composition. Examples of suitable matrices either alone or in combination include but are not limited to hydroxyalkylcelluloses, such as hydroxypropylcellulose and HPMC, hydroxyethyl cellulose, alkylcelluloses such as ethycellulose and methylcellulose, carboxymethylcellulose; sodium carboxymethylcellulose, hydrophilic cellulose derivatives, polyethylene oxide, polyethylene glycol, polyvinylpyrrolidone; ...
Looking for online definition of 3,4-diaminopyridine in the Medical Dictionary? 3,4-diaminopyridine explanation free. What is 3,4-diaminopyridine? Meaning of 3,4-diaminopyridine medical term. What does 3,4-diaminopyridine mean?
Endogenous voltage-gated potassium currents were investigated in human embryonic kidney (HEK293) and Chinese hamster ovary (CHO) cells using whole-cell voltage clamp recording. Depolarizing voltage steps from -70 mV triggered an outwardly rectified current in nontransfected HEK293 cells. This current had an amplitude of 296 pA at +40 mV and a current density of 19.2 pA/pF. The outward current was eliminated by replacing internal K+ with Cs+ and suppressed by the K+ channel blockers tetraethylammonium and 4-aminopyridine. Raising external K+ attenuated the outward current and shifted the reversal potential towards positive potentials as predicted by the Nernst equation. The current had a fast activation phase but inactivated slowly. These features implicate delayed rectifier (I(K))-like channels as mediators of the observed current, which was comparable in size to I(K) currents in many other cells. A small native inward rectifier current but no transient outward current I(A), the M current I(M), ...
Up to 15 patients over the age of 18 years with a diagnosis of LEMS are eligible to enroll if they are medically stable. They may receive 3,4 diaminopyridine in addition to other treatments and standard of care investigations for LEMS under supervision of the primary investigator. Safety laboratory studies and EKGs will be obtained.. The study has been approved by the University of Pittsburgh IRB. There is a local Data-Safety Monitoring Board.. The investigator has a hold on enrolling new subjects. ...
1.) Add solids 1,4,5,8 Naphthalenetetracarboxylic dianhydride (.805 g, 3.00 mmol) and 4-aminopyridine (.847 g, 6.00 mmol)to round bottom flask (I added .8054 g of 1,4,5,8 Naphthalenetetracarboxylic dianhydride, and .8479 g of 4-aminopyridine ...
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Kv4 subunits are the main pore-forming proteins responsible for the fast transient outward currents observed in the CNS (rat brain), where they have been described as A
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Abstract : 2-Aminopyridine (2-AP) and 2,6-diaminopyridine (2,6-DAP) are two derivatives of aminopyridines that act as animportant organic intermediates, mostly used in medicines, dyes and organic sensors. The aim of the study was to evaluate theimpact of biofield energy treatment on isotopic abundance ratios of 2H/1H, 13C/12C, or 15N/14N, in aminopyridine derivativesusing gas chromatography-mass spectrometry (GC-MS). The 2-AP and 2,6-DAP samples were divided into two parts: controland treated. The control sample remained as untreated, while the treated sample was further divided into four groups as T1, T2,T3, and T4. The treated group was subjected to Mr. Trivedis biofield energy treatment. The GC-MS spectra of 2-AP and 2,6-DAP showed five and six m/z peaks respectively due to the molecular ion peak and fragmented peaks of aminopyridinederivatives. The isotopic abundance ratio of 2H/1H, 13C/12C, or 15N/14N were calculated for both the derivatives and significantalteration was found in the ...
4-Aminopyridines undergo surprisingly rapid and highly-selective H/D exchange at C-2 and C-6 in neutral D2O upon microwave irradiation at only 190 °C for 2 h in a sealed vessel. This method contrasts and complements acid-mediated H/D exchange, requires no catalyst and is appropriate for the synthesis of deuterium isotop-ologues of N- and C-substituted 4-aminopyridines and a ben-zofused (quinoline) analogue.. ...
Dalfampridine is a potassium channel blocker. Dalfampridine is used to improve walking in patients with multiple sclerosis (MS). Dalfampridine may also be used for purposes not listed in this medication guide.
Potassium channel blocker information including symptoms, causes, diseases, symptoms, treatments, and other medical and health issues.
Biogen Idec and Acorda Therapeutics said the agreement to market Fampridine-SR (4-aminopyridine) was a sublicensing of an existing license agreement between Acorda and a subsidiary of Elan Corp. The drug is an orally administered, sustained-release drug being developed to improve walking ability in patients with MS.. Under the terms of the agreement, Biogen Idec will commercialize Fampridine-SR and other aminopyridine products in markets outside the United States, and also will have responsibility for regulatory affairs and future clinical development of the drug. In exchange, Acorda will receive an upfront payment of $110 million and additional payments of up to $400 million based on the successful achievement of future regulatory and sales milestones.. The companies said the Food and Drug Administration is reviewing a regulatory approval application for the drug for the U.S. market.. ...
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This paper describes a protocol for imidazo[1,2-a]pyridine-2-carboxylic acids synthesis directly from condensation of substituted 2-aminopyridines and bromopyruvic acid. The recipe is applicable to a wide range of aminopyridines and can be telescoped with an amide formation to obtain Imidazo[1,2-a]pyridine-2-carboxamides in one continuous process.. ...
... : Dalfampridine, or Ampyra, is a potassium channel blocker that is shown to improve visual function, motor skills and relieve fatigue in MS patients.
WASHINGTON (AP) - On the campaign trail, Democratic presidential contender Pete Buttigieg blasts Vice President Mike Pences cultural and religious conservatism. But as the mayor of Indianas...
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Antioxidanty sú látky, ktoré obmedzujú aktivitu voľných radikálov (kyslíkových molekúl) a znižujú ich vznik a minimalizujú ich aktivitu. Týmto obmedzujú proces oxidácie v organizme (starnutie). Z toho dôvodu je dôležitý ich príjem.
TY - JOUR. T1 - Up-regulation of A-type potassium currents protects neurons against cerebral ischemia. AU - Deng, Ping. AU - Pang, Zhi Ping. AU - Lei, Zhigang. AU - Shikano, Sojin. AU - Xiong, Qiaojie. AU - Harvey, Brandon K.. AU - London, Barry. AU - Wang, Yun. AU - Li, Min. AU - Xu, Zao C.. PY - 2011/9/1. Y1 - 2011/9/1. N2 - Excitotoxicity is the major cause of many neurologic disorders including stroke. Potassium currents modulate neuronal excitability and therefore influence the pathological process. A-type potassium current (IA) is one of the major voltage-dependent potassium currents, yet its roles in excitotoxic cell death are not well understood. We report that, following ischemic insults, the IA increases significantly in large aspiny (LA) neurons but not medium spiny (MS) neurons in the striatum, which correlates with the higher resistance of LA neurons to ischemia. Activation of protein kinase Cα increases IA in LA neurons after ischemia. Cultured neurons from transgenic mice lacking ...
Purchase Aminopyridines and Similarly Acting Drugs: Effects on Nerves, Muscles and Synapses - 1st Edition. Print Book & E-Book. ISBN 9780080280004, 9781483150437
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The present protocol describes an efficient, metal-free regioselective synthesis of 2-aroyl-3-arylimidazo[1,2-a]pyridines from 1,3-diaryl-prop-2-en-1-ones and 2-aminopyridine. The iodine-NH4OAc promoted reaction offers a novel route in the synthesis of 2-aroyl-3-arylimidazo[1,2-a]pyridines. This protocol off
Acorda Therapeutics, Inc. (Nasdaq: ACOR) today announced that the MILESTONE clinical study did not show sufficient efficacy to support further development of dalfampridine to improve post-stroke walking difficulties (PSWD)....ACOR
Tetraethylammonium bis[1,2-benzenediolato(2-)-o,o]-borate/ACM53992920 can be provided in Alfa Chemistry. We are dedicated to provide our customers the best products and services.
At Virginia Commonwealth University (VCU), researchers sought to shed light on the biopsychosocial and spiritual effects of taking prescribed opioids to treat noncancer pain.
Poly(methacrylic acid-ethylene glycol dimethacrylate) was prepared using 2-aminopyridine as the imprinting molecule. This molecularly imprinted polymer (MIP) was ground and packed into a micro-column for selective solid phase extraction (SPE) of 2-aminopyridine from 20μl of sample solution. Non-specific adsorption was also confirmed for a structural analogue. Interestingly one of the isomers, 4-aminopyridine, bound most strongly to the MIP. The implication of resonance and basicity of this isomer molecule can be used to explain its strong binding with the self-assembled functional methacrylic acid (MAA) monomer. The monomer template complexion process was evaluated by Scatchard plots to determine a binding constant. The binding constant value is important for predicting the selectivity of a new MIP. After optimization of the molecular recognition process, a molecularly imprinted solid phase extraction-differential pulsed elution (MISPE-DPE) method was developed for the selective determination ...
The anterior aorta of Aplysia is innervated by nerves arising from the abdominal ganglion (Sawada et al., 1981a). The vulvar nerve is one of the nerves innervating the anterior aorta, in which axons of some identifiable motoneurons or modulatory neurons for the anterior aorta are contained (Sawada et al., 1981a, 1984c). The phasic contraction evoked by the vulvar nerve stimulation was inhibited by the enterins. At least, one of the mechanisms for the inhibition seems to be activation of K+ conductance of the muscle membrane. We found that the enterins hyperpolarize the membrane potential of the muscle fibers via the activation of 4-AP-sensitive K+ channels. Sensitivity of the K+ channels to 4-AP is quite high, and EC50 of 4-AP was,10-6 mol l-1. The value is comparable to another highly 4-AP-sensitive K+ channel described in the accessory radula closer muscle of Aplysia (Brezina et al., 1994). The enterin-induced hyperpolarization of the muscle membrane should, in principle, reduce the ...
Pyridyne in chemistry is the pyridine analogue of benzyne. This reactive intermediate is of some importance to scientific research. Pyridynes are the class of compounds sharing the pyridyne building motif. Two isomers exist, the 2,3-pyridine (2,3-didehydropyridine) and the 3,4-pyridyne (3,4-didehydropyridine). The reaction of 3-bromo-4-chloropyridine with furan and lithium amalgam gives 1,4-epoxy-dihydroquinoline through the 2,3-pyridyne intermediate. The reaction of 4-bromopyridine with sodium in liquid ammonia gives both 3-aminopyridine and 4-aminopyridine through the 3,4-pyridyne intermediate and an E1cB-elimination reaction. Pyridynes were first postulated by Levine and Leake in 1955. In 1969 Zoltewicz and Nisi trapped 3,4-pyridyne in a reaction of 3-bromopyridine with methylmercaptan and sodium amide in ammonia. The methylthio and amino pyridines were found to be formed in the same ratio. In 1972 Kramer and Berry inferred the formation of 3,4-pyridyne in gas-phase photolysis of ...
The effects of 4-aminopyridine (4AP) on the extracellularly recorded nerve terminal action potential (NTAP) and end-plate potential were studied at the frog neuromuscular junction. An in-depth analysis of the time course of the NTAP was performed in the presence and absence of extracellular Ca++. Low concentrations (5 X 10(-6) M) of 4AP produced no significant alterations in the time course of the NTAP, yet increased quantal content of the end-plate potential 2-fold. In contrast, high concentrations (5 X 10(-4) M) of 4AP prolonged the duration of the NTAP by selectively flattening the K+ slope of the NTAP and increased the quantal content of the end-plate potential. It is concluded that both potassium channel blockade and facilitation of transmitter release by 4AP can be demonstrated in this preparation, and that it is possible to separate these actions by varying the concentration of 4AP. Interpretation of these data suggests that there is a second site or mechanism of action by which 4AP ...
2013 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by Organometallics, American Chemical Society. It incorporates referees comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/om400326c ...
The Chichibabin reaction (pronounced (chē)-chē-bā-bēn) is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction: The direct amination of pyridine with sodium amide takes place in liquid ammonia. Following the addition elimination mechanism first a nucleophilic NH2− is added while a hydride (H−) is leaving. Ciganek describes an example of an intramolecular Chichibabin reaction in which a nitrile group on a fused ring is the source of nitrogen in amination. It is widely accepted that the Chichibabin reaction mechanism is an addition-elimination reaction that proceeds through an σ-adduct (Meisenheimer adduct) intermediate (the third structure). First, the nucleophilic NH2− group adds to the δ+ ring carbon pushing electrons onto the ring nitrogen and forming the anionic σ-adduct, which is stabilized by sodium. Electrons from the ...
in assassin vs asasssin(like BlackRusian, he have ~3,5k ap) rest items: Iron Set, LB+1, Rol+1, RE+3, HR+2, krowaz set+7 2610 ap on wolf(in full krowaz
This study aims to determine whether 4-aminopyridine (4AP) can reduce attacks of ataxia in patients with episodic ataxia type 2 (EA2), a rare but often debilitating condition. Episodic ataxia (EA) is a group of inherited disorders characterized by recurrent, discrete episodes of vertigo and ataxia variably associated with progressive ataxia. EA2, the most common and the best characterized of all the EA syndromes, is caused by heterozygous mutations in CACNA1A, which encodes the main subunit of a neuronal voltage-gated calcium channel, Cav2.1.. Although observational data suggest symptomatic resolution with acetazolamide in many EA2 patients, the investigators found in our patient databases that at least a third of the EA2 patients continue to suffer debilitating ataxia attacks, either because of incomplete control while on acetazolamide or because of intolerability or hypersensitivity to acetazolamide. For these patients there is no alternative intervention. 4-Aminopyridine (4AP) has been found ...
The present study demonstrates that Ito1 introduced into freshly isolated guinea pig myocytes by cell fusion substantially changes the early repolarization phase and abbreviates action potential duration. The role of Ito1 in the action potential has been previously assessed indirectly by comparison of Ito1 densities and action potentials throughout the layers of the myocardial wall (ie, humans,24 25 dogs,29 30 31 cats,32 rats,33 and rabbits34 ) or in disease states such as hypertrophy and heart failure.1 2 3 To further elucidate the role of Ito1, Ito1 has been blocked pharmacologically, knocked out by dominant-negative constructs, or artificially introduced into heart failure cells with brief repolarizing current pulses.2 6 33 35 However, K+ channel blockers such as 4-aminopyridine also exhibit nonspecific effects,33 current pulses may lack physiological current kinetics, and previous knockout studies were limited by changes of gene expression during cell culture6 or adaptive upregulation of ...
Lenovo unveiled the ThinkPad X1 Carbon officially in China yesterday. We already reported about the ThinkPad X1 Carbon back in May when Wired Magazine fondled it.. Get the Free Tracker App to find 2018 NES Classic in Stock. The Lenovo ThinkPad X1 Carbon is substantial upgrade to the currently available ThinkPad X1. Features include 14-inch screen, 1,600x900px screen, Dolby Home Theater v4, 720p HD camera, face tracking, backlit keyboard and Ivy Bridge CPUs. The 14-inch ThinkPad X1 Carbon weighs only 3 pounds and only 18mm thin. It packs ivy Bridge Intel CPUs and other options. Pricing is still a mystery. Via AP on Yahoo!.. ...
SEATTLE (AP) - On his return from China last week, Dr. Ian Lipkin quarantined himself in his basement. His wife now puts his food on the stairs. He
Title:Aminopyridines and Acetyl-DL-leucine: New Therapies in Cerebellar Disorders. VOLUME: 17 ISSUE: 1. Author(s):Roger Kalla and Michael Strupp*. Affiliation:Department of Neurology, German Center for Vertigo and Balance Disorders, and Institute for Clinical Neurosciences, University Hospital Munich, Campus Grosshadern, Munich, Department of Neurology, German Center for Vertigo and Balance Disorders, and Institute for Clinical Neurosciences, University Hospital Munich, Campus Grosshadern, Munich. Keywords:Cerebellar ataxia, central vestibular disorders, aminopyridines, 4-aminopyridine, episodic ataxia type 2, downbeat nystagmus, acetyl-DL-leucine.. Abstract:Cerebellar ataxia is a frequent and often disabling syndrome severely impairing motor functioning and quality of life. Patients suffer from reduced mobility, and restricted autonomy, experiencing an even lower quality of life than, e.g., stroke survivors. Aminopyridines have been demonstrated viable for the symptomatic treatment of certain ...
DUGi: Viewing Item from repository DUGiDocs: Peptide conjugates incorporating the red-ox active ligands Me2PyTACN or (S,S)-BPBP at the N- or the C-terminus of the cell-penetrating peptide BP16 were synthesized (PyTACN-BP16 (BP341), BP16-PyTACN (BP342), BPBP-BP16 (BP343), and BP16-BPBP (BP344)). Metal binding peptides bearing at the N-terminus the ligand, an additional Lys and a β-Ala were also prepared (PyTACN-βAK-BP16 (BP345) and BPBP-βAK-BP16 (BP346)). Moreover, taking into account the clathrin-dependent endocytic mechanism of BP16, the enzymatic cleavable tetrapeptide Gly-Phe-Leu-Gly was incorporated between the ligand and the N- or C-terminus of BP16 (BPBP-GFLG-BP16 (BP347) and BP16-GLFG-BPBP (BP348). Analysis of the cytotoxicity of all the peptide conjugates showed that: (i) the position of the ligand influenced the IC50 values, (ii) the incorporation of the βAla-Lys dipeptide rendered non active sequences, (iii) peptide conjugates derived from the (S,S)-BPBP ligand were more active than
Solari, A.; Uitdehaag, B.; Giuliani, G.; Pucci, E.; Taus, C. (2002). "Aminopyridines for symptomatic treatment in multiple ... Sedehizadeh, S; Keogh, M; Maddison, P (2012). "The use of aminopyridines in neurological disorders". Clinical neuropharmacology ... 3,4-DAP was discovered in Scotland in the 1970s, and doctors in Sweden first showed its use in LEMS in the 1980s. In the 1990s ... A 2011 Cochrane review compared the cost of the 3,4-DAP and 3,4-DAPP in the UK and found an average price for 3,4-DAP base of £ ...
Gu Y, Kirkman-Brown JC, Korchev Y, Barratt CL, Publicover SJ (October 2004). "Multi-state, 4-aminopyridine-sensitive ion ...
The duration of effects in animals lasts up to 4 hours. Xylazine users are more likely to be male, under the age of 30, living ... 11 (4): 295-313. doi:10.1111/j.1365-2885.1988.tb00189.x. PMID 3062194. Xylazine at drugs.com by Patricia M. Dowling & Johann ( ... Combining yohimbine and 4-aminopyridine in an effort to antagonize xylazine is superior as compared to the administration of ... 4 (2): 128-34. PMID 14506588. Veilleux-Lemieux, D; Castel, A; Carrier, D; Beaudry, F; Vachon, P (September 2013). " ...
"4-Aminopyridine and the early outward current of sheep cardiac Purkinje fibers". J Gen Physiol 1979;73:139-157. Zygmunt AC, ... Li GR, Feng J, Wang Z, Fermini B, Nattel S. "Comparative mechanisms of 4-aminopyridine-resistant Ito in human and rabbit atrial ...
http://serbiosoc.org.rs/arch_old/VOL62/SVESKA_4/21%20-%20Pathak.pdf Angstadt, JD; Choo, JJ (1996). "Sodium-dependent plateau ... 2010), MODULATION OF NICKEL-INDUCED BURSTING WITH 4-AMINOPYRIDINE IN LEECH RETZIUS NERVE CELLS. ...
4 (3): 247. doi:10.1111/j.1527-3458.1998.tb00067.x. Damulin, IV; Stepkina, DA; Lokshina, AB (2011). "Neuromidin in mixed ... 111 (4 Pt 2): 23-7. PMID 23120773. Onodera, K; Kojima, J; Wachi, M (1998). "Ipidacrine (NIK-247), a novel antidementia, rapidly ... This compound is a derivative of 4-aminopyridine and is structurally similar to tacrine. Ipidacrine is a reversible ...
DRC-1339 is limited to USDA use only, while 4-AP is a restricted-use pesticide, for use only by licensed applicators. The use ... Retrieved 4 January 2017. Levi, Wendell (1977). The Pigeon. Sumter, S.C.: Levi Publishing Co, Inc. ISBN 0-85390-013-2. Johnston ... 14 (4): 251-255. doi:10.1089/vbz.2011.0943. PMID 24661012. Osman, Kamelia M.; Mehrez, Mona; Erfan, Ahmed M.; Al Atfeehy, ... Retrieved January 4, 2017. Reinoso, V.; Katani, R.; Barbato, G. F. (2007). "Nicarbazin reduces egg production and fertility in ...
Apr;19(4):497-503. J. P. Hendrix (1949. "Neostigmine as antidote to Etamon®." JAMA 139(11) 733-734. S. W. Hoobler, G. K. Moe ... "Ion dependence of the release of noradrenaline by tetraethylammonium and 4-aminopyridine from cat splenic slices." Br. J. ...
17 (4): 151-55. doi:10.1016/0166-2236(94)90092-2. Ahasan, H A M N, A. A. Mamun, S. R. Karim, M. A. Baker, E. A. Gazi, and C. S ... 50 (4): 1117-122. doi:10.1111/j.1471-4159.1988.tb10581.x. Buzanska, L.; Zablocka, B.; Dybel, A.; Domanska-Janik, K.; Albrecht, ... 24 (4): 512-18. doi:10.1111/j.1530-0277.2000.tb02019.x. Hensley, K (1994). "A Model for β-Amyloid Aggregation and Neurotoxicity ... 19 (4): 488-96. doi:10.1002/(sici)1097-4598(199604)19:4. 3.0.co;2-8. Rothman, S.; Thurston, J.; Hauhart, R. (1987). "Delayed ...
... has also been shown to abolish [3H]Glu release after in vivo exposure to 4-aminopyridine (4-AP) which suggests an ... with full remission typically occurring within 3-4 weeks. Vinpocetine has been reported to have cerebral blood-flow enhancing ... "Vinpocetine inhibits glutamate release induced by the convulsive agent 4-aminopyridine more potently than several antiepileptic ...
123 (4): 387-400. doi:10.1085/jgp.200308976. PMC 2217458 . PMID 15024041. Thébaud B, Michelakis ED, Wu XC, Moudgil R, Kuzyk M, ... 57 (4): 473-508. doi:10.1124/pr.57.4.10. PMID 16382104. Shah NH, Aizenman E (February 2014). "Voltage-gated potassium channels ... 4 (1): 60-70. doi:10.1007/s11481-008-9106-6. PMC 3974578 . PMID 18459047. Kondratskyi A, Kondratska K, Skryma R, Prevarskaya N ... 8 (4): e2737. doi:10.1038/cddis.2017.160. Swartz KJ (February 2007). "Tarantula toxins interacting with voltage sensors in ...
28 (4): 539-46. doi:10.1002/ana.410280411. PMID 2252365. Faden AI, Lemke M, Simon RP, Noble LJ (1988). "N-methyl-D-aspartate ... 4 (4): 281-6. doi:10.1080/13651500050517830. Basile AS, Huang JM, Xie C, Webster D, Berlin C, Skolnick P (December 1996). "N- ... 80 (1): 111-4. doi:10.1016/0304-3940(87)90505-2. PMID 2821457. Ramoa AS, Alkondon M, Aracava Y, et al. (July 1990). "The ... 35 (4): 407-14. doi:10.1016/0028-3908(96)00006-8. PMID 8793902. Iravani MM, Muscat R, Kruk ZL (June 1999). "MK-801 interaction ...
4-membered rings can be obtained by [2+2]cycloadditions for instance with benzyne. An example of a 1,3-dipolar cycloaddition to ... 199 (3-4): 373. Bibcode:1992CPL...199..373C. doi:10.1016/0009-2614(92)80134-W. Ohtsuki, T.; Ohno, K.; Shiga, K.; Kawazoe, Y.; ... The trimer has also been reported using 4-aminopyridine as catalyst (4% yield) and observed with scanning tunneling microscopy ... 4-cycloaddition of a fullerene". Journal of the Chemical Society, Perkin Transactions 2 (10): 2079. doi:10.1039/P29960002079. ...
... (4-PNA), also known as N-(pyridin-4-yl)nicotinamide, is a kinked dipodal dipyridine which was originally ... Kraft, P. E.; Laduca, R. L. (2012). "Catena-Poly\\tetra-μ-benzoato-κ8O:O′-dicopper(II)]-μ-\N-(pyridin-4-yl)nicotinamide]-κ2N:N ... It is synthesized through the reaction of nicotinoyl chloride and 4-aminopyridine. Gardner, T. S.; Wenis, E.; Lee, J. (1954). " ... dibenzoato-κ2O-copper(II)]-μ-\N-(pyridin-4-yl)nicotinamide]-κ2N:N′]". Acta Crystallographica Section E. 68 (8): m1049. doi: ...
40 (4): 551-9. doi:10.1016/S0028-3908(00)00189-1. PMID 11249964. Kindler CH, Paul M, Zou H, Liu C, Winegar BD, Gray AT, Yost CS ... 8 (4): 345-52. doi:10.1007/s11910-008-0053-7. PMC 2587091 . PMID 18590620. Doyle DA, Morais Cabral J, Pfuetzner RA, Kuo A, ... 431 (7010): 830-4. Bibcode:2004Natur.431..830N. doi:10.1038/nature02943. PMID 15483608. Varma S, Rempe SB (Aug 2007). "Tuning ... doi:10.1007/978-4-319-21756-7_9. Rang, HP (2003). Pharmacology. Edinburgh: Churchill Livingstone. p. 60. ISBN 0-443-07145-4. ...
As a member of the aminopyridine class, besipirdine enhances the release of acetylcholine by blocking M-channels, voltage-gated ... 300 (1-2): 71-4. doi:10.1016/0014-2999(96)00002-7. PMID 8741167. Francis, P. T.; Palmer, A. M.; Snape, M; Wilcock, G. K. (1999 ... Its N-despropyl metabolite, P86-7480, exhibits transient vasoconstrictor effects, producing a pressor effect of 16 ± 4 mm Hg ... Besipirdine (besipirdine hydrochloride, or HP749), an indole-substituted analog of 4-aminopyridine, is a nootropic drug ...
57 (4): 473-508. doi:10.1124/pr.57.4.10. PMID 16382104. Lien CC, Jonas P (March 2003). "Kv3 potassium conductance is necessary ... 57 (4): 473-508. doi:10.1124/pr.57.4.10. PMID 16382104. "Entrez Gene: KCNC1 potassium voltage-gated channel, Shaw-related ... The overlapping sensitivity of potassium current to both 0.5 mM TEA and 30 μM 4-AP strongly suggest an action on Kv3.1 subunits ... Kv3.1 currents in heterologous systems are highly sensitive to external tetraethylammonium (TEA) or 4-aminopyridine (4-AP) ( ...
The molecular formula C5H6N2 may refer to: Aminopyridines 2-Aminopyridine 3-Aminopyridine 4-Aminopyridine Diazepines 1,2- ...
57 (4): 473-508. doi:10.1124/pr.57.4.10. PMID 16382104. Gutman GA, Chandy KG, Grissmer S, Lazdunski M, McKinnon D, Pardo LA, ... 4 (12): 711-5. doi:10.1007/BF00357794. PMID 8111118. Gutman GA, Chandy KG, Grissmer S, Lazdunski M, McKinnon D, Pardo LA, ... 57 (4): 473-508. doi:10.1124/pr.57.4.10. PMID 16382104. Kolodin YO (2008-04-27). "Ionic conductances underlying excitability in ... Kv3.2 currents in heterologous systems are highly sensitive to external tetraethylammonium (TEA) or 4-aminopyridine (4-AP) ( ...
Commonly used avicides include strychnine, DRC-1339 (3-chloro-4-methylaniline hydrochloride, Starlicide) and CPTH (3-chloro-p- ... 4-aminopyridine). Chloralose is also used as an avicide. In the past, highly concentrated formulations of parathion in diesel ... 4-Aminopyridine Exposure of nontarget birds to DRC-1339 avicide in fall baited sunflower fields BIOONE Online Journals - BIOONE ...
131 (4): 438-44. doi:10.1016/j.otohns.2004.02.046. PMID 15467614. Cohen, HS (2004). "Side-lying as an alternative to the Dix- ... 139 (5 Suppl 4): S47-81. doi:10.1016/j.otohns.2008.08.022. PMID 18973840. Lay summary - AAO-HNS (2008-11-01). Dickson, Gretchen ... 25 (2): 130-4. doi:10.1097/00129492-200403000-00008. PMID 15021771. Buchholz, D. Heal Your Headache. New York:Workman ... and 4-aminopyridine for the treatment of episodic ataxia type 2 and both downbeat and upbeat nystagmus. These drug therapies ...
22 (4): 859-77, vii. doi:10.1016/j.cger.2006.06.011. PMID 17000340. Ilg W, Synofzik M, Brötz D, Burkard S, Giese MA, Schöls L ( ... 4 (6): 349-61. doi:10.1016/S1474-4422(05)70096-X. PMID 15907739. Moeller JJ, Macaulay RJ, Valdmanis PN, Weston LE, Rouleau GA, ... ISBN 0-87893-060-4. Fonteyn EM, Schmitz-Hübsch T, Verstappen CC, Baliko L, Bloem BR, Boesch S, Bunn L, Charles P, Dürr A, Filla ... 20 (4): 497-500. doi:10.1002/mds.20375. PMID 15645525. Schmitz TJ, O'Sullivan SB (2007). "Examination of Coordination". ...
... aminopyridines MeSH D03.383.725.050.060 --- 4-aminopyridine MeSH D03.383.725.050.085 --- amrinone MeSH D03.383.725.050.085.543 ... 4,5-tetrahydro-8-chloro-3-methyl-5-phenyl-1h-3-benzazepin-7-ol MeSH D03.438.079.800 --- 2,3,4,5-tetrahydro-7,8-dihydroxy-1- ... 4,5-dihydro-1-(3-(trifluoromethyl)phenyl)-1h-pyrazol-3-amine MeSH D03.383.129.539.200 --- epirizole MeSH D03.383.129.539.487 ... 4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, methyl ester MeSH D03.383.725.210 --- dimethindene MeSH D03.383. ...
"4-Aminopyridine". pmep.cce.cornell.edu. Retrieved 2017-11-19. Toxicity Antibiotic. ...
4,4'-(3-oxo-1,5-pentanediyl)bis(n,n-dimethyl-n-2-propenyl-), dibromide MeSH D02.092.146.325 --- p-dimethylaminoazobenzene MeSH ... 4,5-trisphosphate MeSH D02.033.800.519.400.700 --- phytic acid MeSH D02.033.800.609 --- mannitol MeSH D02.033.800.609.450 --- ... 4-nitrophenyl) ester MeSH D02.705.539.783 --- phorate MeSH D02.705.539.790 --- phosmet MeSH D02.705.539.900 --- temefos MeSH ... 4-nitrophenyl) ester MeSH D02.886.309.783 --- phorate MeSH D02.886.309.790 --- phosmet MeSH D02.886.309.900 --- temefos MeSH ...
196 (1): 4-12. doi:10.1192/bjp.bp.108.062984. PMID 20044651.. *^ Stein DJ, Zungu-Dirwayi N, Seedat S (2000). Stein D, ed. " ... 194 (1): 4-9. doi:10.1192/bjp.bp.107.048504. PMID 19118318.. *^ Reid JG, Gitlin MJ, Altshuler LL (July 2013). "Lamotrigine in ... 36 (4): 131-2. doi:10.1097/WNF.0b013e318294799a. PMID 23783003.. *^ "Safety Alerts for Human Medical Products - Lamictal ( ... doi:10.1016/S0149-2918(03)80314-4. PMID 14667954.. *^ Wiffen PJ, Derry S, Moore RA (December 2013). "Lamotrigine for chronic ...
4-Aminopyridines undergo surprisingly rapid and highly-selective H/D exchange at C-2 and C-6 in neutral D2O upon microwave ... Bagley, Mark C, Alnomsy, Ayed and Sharhan, Hussein I (2016) Rapid protium-deuterium exchange of 4-aminopyridines in neutral D2O ... Rapid protium-deuterium exchange of 4-aminopyridines in neutral D2O under microwave irradiation ... and C-substituted 4-aminopyridines and a ben-zofused (quinoline) analogue. ...
Aminopyridines and Acetyl-DL-leucine: New Therapies in Cerebellar Disorders. Author(s): Roger Kalla, Department of Neurology, ... Aminopyridines have been demonstrated viable for the symptomatic treatment of certain forms of cerebellar ataxia. This article ... Aminopyridines have been demonstrated viable for the symptomatic treatment of certain forms of cerebellar ataxia. This article ... Strupp, M.; Teufel, J.; Zwergal, A.; Schniepp, R.; Khodakhah, K.; Feil, K. Aminopyridines for the treatment of neurologic ...
The frequency of spontaneous inter-ictal bursting induced by picrotoxin, high-K(+), or 4-aminopyridine was significantly ... The frequency of spontaneous inter-ictal bursting induced by picrotoxin, high-K(+), or 4-aminopyridine was significantly ...
... but it is insensitive to the classical broad-spectrum potassium channel blocking drugs 4-aminopyridine and tetraethylammonium ...
Other articles where 4-aminopyridine is discussed: drug: Drugs that affect skeletal muscle: …acetylcholine release, including ... tetraethylammonium and 4-aminopyridine. They work by blocking potassium-selective channels in the nerve membrane, thereby ... acetylcholine release, including tetraethylammonium and 4-aminopyridine. They work by blocking potassium-selective channels in ...
"Aminopyridines for symptomatic treatment in multiple sclerosis". Cochrane Database Syst Rev (4): CD001330. doi:10.1002/14651858 ... Octopus Envenomations at eMedicine.com Wu, ZZ; Li, DP; Chen, SR; Pan, HL (2009). "Aminopyridines Potentiate Synaptic and ... The use of 4-aminopyridine in bird control has been criticized by the Humane Society of the United States. Fampridine has been ... 4-Aminopyridine is also used under the trade name Avitrol as 0.5% or 1% in bird control bait. It causes convulsions and, ...
The 4-AP content of the pill that was ingested by the patient was at least 8 times greater (,80 mg) than the standard. The ... She was receiving 4-AP for more than 3 years. The symptoms started soon after the ingestion of a single pill that was supposed ... 4-Aminopyridine (4-AP) is a drug that is used to improve motor fatigue in patients suffering from multiple sclerosis (MS). ... 4-AP is a potassium channel-blocking drug. The prolongation of the action potential may facilitate calcium entry into the cell ...
2004 Mar 4;41(5):701-10. van Diemen HA, Polman CH, van Dongen TM, van Loenen AC, Nauta JJ, Taphoorn MJ, van Walbeek HK, ... 4-Aminopyridine in Episodic Ataxia Type 2 (4AP in EA2). The recruitment status of this study is unknown. The completion date ... Epub 2009 Dec 4. Spyker DA, Lynch C, Shabanowitz J, Sinn JA. Poisoning with 4-aminopyridine: report of three cases. Clin ... 1980 Jun;16(4):487-97. Stefoski D, Davis FA, Faut M, Schauf CL. 4-Aminopyridine improves clinical signs in multiple sclerosis. ...
4-aminopyridine and cerebellar gait: a retrospective case series.. [Roman Schniepp, Max Wuehr, Maximilian Neuhaeusser, Ann ...
What is 4-aminopyridine? Meaning of 4-aminopyridine medical term. What does 4-aminopyridine mean? ... Looking for online definition of 4-aminopyridine in the Medical Dictionary? 4-aminopyridine explanation free. ... 4-aminopyridine. Also found in: Encyclopedia, Wikipedia. 4-aminopyridine. 1. a central nervous system stimulant and a ... The drug 4-aminopyridine partially restores some sensory and motor functions in one-third of patients who have been paralyzed ...
Until recently, I have been reluctant to post much about 4-aminopyridine (4-AP) or fampridine for three reasons. First, ... How should I ramp up on the dose of 4-AP to avoid side-effects when I start taking the drug? Experience in clinical trials of 4 ... What is the safest way for me to increase the dose of 4-AP beyond 10 mg every six hours. If you are getting benefits from an ... How long should I take 4-AP before I know that it is effective or not? The effects of 4-AP should be apparent within an hour ...
A randomised double-blind, cross-over trial of 4-aminopyridine for downbeat nystagmus-effects on slowphase eye velocity, ...
... aminopyridine (4AP) is strongly concentration-dependent. Different 4AP concentrations are characterized by qualitatively ... Timothy L Myers1,2, Oscar C Gonzalez3,4, Jacob B Stein2 and Maxim Bazhenov3*. 1Neuroscience Graduate Program, University of ... Epilepsy J 4:128. DOI: 10.4172/2472-0895.1000128 Copyright: © 2018 Myers TL, et al. This is an open-access article distributed ... 4Neuroscience Graduate Program, University of California, San Diego, California, United States of America. *Corresponding ...
Leptin inhibits 4-aminopyridine- and pentylenetetrazole-induced seizures and AMPAR-mediated synaptic transmission in rodents. ... Leptin inhibits 4-aminopyridine- and pentylenetetrazole-induced seizures and AMPAR-mediated synaptic transmission in rodents. ... Focal seizures in rats were induced by neocortical injections of 4-aminopyridine, an inhibitor of voltage-gated K+ channels. ... Leptin inhibited α-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) receptor-mediated synaptic transmission in mouse ...
4-Aminopyridine, Atenolol, or Placebo in Patients With Vestibular Migraine. The safety and scientific validity of this study is ...
Aminopyridines and the treatment of spinal cord injury. J Neurotrauma. 1993 Spring;10(1):19-24. Review. ... High Doses of 4-aminopyridine in Clinically Complete Chronic Spinal Cord Injury Patients.. The safety and scientific validity ... 1993 Apr;31(4):216-24. Hayes KC, Potter PJ, Wolfe DL, Hsieh JT, Delaney GA, Blight AR. 4-Aminopyridine-sensitive neurologic ... Drug: 4-Aminopyridine Each patient will take 10 mg per kilogram of weight (example: a person weighing 60 kg, will take two ...
Cholinergic mechanisms in heart: interactions with 4-aminopyridine. Message Subject (Your Name) has forwarded a page to you ... 4-Aminopyridine lengthened the action potential and increased spike amplitude. These effects were not frequency-dependent but ...
Effect of 4-aminopyridine on nerve terminal action potentials. Message Subject (Your Name) has forwarded a page to you from ... Effect of 4-aminopyridine on nerve terminal action potentials.. E S Burley and R S Jacobs ... Effect of 4-aminopyridine on nerve terminal action potentials.. E S Burley and R S Jacobs ... Effect of 4-aminopyridine on nerve terminal action potentials.. E S Burley and R S Jacobs ...
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3-aminopyridine)-4-phenyl-1-azabuta-1,3-diene as new heterodienes for iron carbonyl complexes. ... Keywords: 2-Aminopyridine; 3-aminopyridine; heterodiene; cinnamaldehyde; Schiff base 2-Aminopyridine; 3-aminopyridine; ... In this paper we propose the synthesis of 1-(2-aminopyridine)-4-phenyl-1-azabuta-1,3-diene and 1-(3-aminopyridine)-4-phenyl-1- ... Jarrahpour, A.A.; Esmaeilbeig, A.R.; Adabi Ardekani, A. Synthesis of 1-(2-aminopyridine)-4-phenyl-1-azabuta-1,3-diene and 1-(3- ...
One of the most prominent avicides, Avitrol -the trade name for 4-aminopyridine-i s available as grain baits or powder ... A similar event happened in Schenectady New York in 2006, when Rentokill, Inc., a local exterminator applied 4-aminopyridine in ... stuffed with 4-aminopyridine laced corn was the culprit. The chemical was set out on the roof of a building in effort to ward ...
Request sample of market research report on Europe 4 Aminopyridine Market Report 2017. Explore detailed TOC, tables and figures ... 5.3 UK 4-Aminopyridine Sales and Market Share by Type. 5.4 UK 4-Aminopyridine Sales and Market Share by Application. 6 Russia 4 ... Aminopyridine (Volume, Value and Sales Price). 6.1 Russia 4-Aminopyridine Sales and Value (2012-2017). 6.1.1 Russia 4- ... Aminopyridine Sales and Growth Rate (2012-2017). 6.1.2 Russia 4-Aminopyridine Revenue and Growth Rate (2012-2017). 6.1.6 Russia ...
... aims at providing comprehensive data on 4- ... 4-Aminopyridine-2,6-Dicarboxylic Acid (CAS 2683-49-0) Market Research Report 2018. Date:. January 15, 2018 ... 4-aminopyridine-2,6-dicarboxylic acid prices in other regions. 7. 4-AMINOPYRIDINE-2,6-DICARBOXYLIC ACID END-USE SECTOR 7.1. 4- ... aminopyridine-2,6-dicarboxylic acid market by application sphere. 7.2. 4-aminopyridine-2,6-dicarboxylic acid downstream markets ...
GERMINE MONOACETATE, 4-AMINOPYRIDINE AND SUCCINYLCHOLINE You will receive an email whenever this article is corrected, updated ... GERMINE MONOACETATE, 4-AMINOPYRIDINE AND SUCCINYLCHOLINE. Anesthesiology 9 1980, Vol.53, S280. doi: ... N. N. Durant, C. Lee, R. L. Katz; GERMINE MONOACETATE, 4-AMINOPYRIDINE AND SUCCINYLCHOLINE. Anesthesiology 1980;53(3 Suppl): ...
2-Chloro-4-methoxyphenoxy)quinoxaline-2-carbonyl]amino]pyridine-2-carboxylic acid , C22H15ClN4O5 , CID 78319372 - structure, ...
  • 4-Aminopyridine (4AP) increases evoked excitatory as well as inhibitory synaptic transmission in the spinal cord (Brain Research, 240 (1982) 117), enhances interneuronal spontaneous activity and partly restores impaired spinal cord functions (Neuroscience, 126 (2004) 511). (edu.mx)
  • The extracellular parameters evaluated in areas CA3 and CAI were: (1) interictal-type bursting, (2) evoked population spike (PS) amplitude, (3) latency to PS onset, and (4) duration of the excitatory postsynaptic potential (EPSP). (deepdyve.com)
  • 4-AP caused a voltage-dependent reduction in mean open time of K DR . Relief of 4-AP block of whole cell currents during washout required channel activation and was unaffected by voltage. (ahajournals.org)
  • A feature of 4-AP block of K DR was identified that was not mimicked by homotetrameric Kv1.5 channels, but was apparent in recordings of Kv1.2 currents, as well as currents due to heteromultimeric association of Kv1.2 and Kv1.5. (ahajournals.org)
  • The biophysical and pharmacological effects of individual phenylalanine-for-leucine (Phe-for-Leu) substitutions in the leucine heptad repeat region located at the cytosolic surface of the channel pore, on whole-cell K + currents, were studied in cloned and mutated human brain Kvl.4 K + channels (hKvl.4) transiently transfected into HeLa cells. (aspetjournals.org)
  • KA) channel currents, which are highly sensitive to 4-aminopyridine , and slowly inactivated or noninactivated currents such as delayed rectifying [K.sup. (thefreedictionary.com)
  • i) Outward potassium currents, (ii) which are sensitive to 10 mM 4-AP, were detected in M-RV-GFP(D) cells. (nih.gov)
  • iv) Currents obtained by subtracting the current in the presence of 4-AP from that in the absence of the inhibitor. (nih.gov)
  • 28 29 30 31 At physiological Cl − concentrations, the reversal potential for Cl − currents has been estimated at values ranging from −65 to −30 mV. 26 32 33 Thus, Cl − current can play a role both in the repolarization of the cell from plateau potentials and in phase 4 depolarization underlying spontaneous activity. (ahajournals.org)
  • Leptin inhibited α-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) receptor-mediated synaptic transmission in mouse hippocampal slices but failed to inhibit synaptic responses in slices from leptin receptor-deficient db/db mice. (jci.org)
  • Aminopyridines and Similarly Acting Drugs: Effects on Nerves, Muscles and Synapses presents the proceedings of a IUPHAR Satellite Symposium in conjunction with the eighth International Congress of Pharmacology held in Paris, France on July 27-29, 1981. (elsevier.com)
  • Journal of Pharmacy and Pharmacology , 45 (4), 242-245. (rug.nl)
  • Journal of Pharmacy and Pharmacology , 36 (4), 235-239. (rug.nl)
  • In the laboratory, 4-AP is a useful pharmacological tool in studying various potassium conductances in physiology and biophysics. (wikipedia.org)
  • Decades of research have focused on understanding the mechanisms leading to the development of seizure-like activity using various pro-convulsive pharmacological agents, including 4-aimnopyridine (4AP). (omicsonline.org)
  • 1985). THE PHARMACOLOGICAL CHARACTERIZATION OF 3,4-DIHYDROXYPHENYLIMINO-2-IMIDAZOLIDINE (DPI) AS A POTENT MIXED ALPHA-1/ALPHA-2-ADRENOCEPTOR AGONIST RATHER THAN AS A DOPAMINE RECEPTOR AGONIST . (rug.nl)
  • Similarly, IA and ID antagonist 4-aminopyridine (4AP) has been shown, in in vivo and in vitro studies, to cause hyperexcitability and the development of seizure-like epileptiform discharges [ 15 - 23 ]. (omicsonline.org)
  • The results show that 4-AP induced changes in vitro can help differentiate drugs with similar in vivo spectrums of anticonvulsant activity. (deepdyve.com)
  • Tapia, "Paired pulse facilitation is turned into paired pulse depression in hippocampal slices after epilepsy induced by 4-aminopyridine in vivo," Neuropharmacology, vol. (thefreedictionary.com)
  • Inhibition by 4-aminopyridine (4-AP) of K DR of rabbit portal vein (RPV) myocytes was studied by patch clamp and compared with that of channels composed of Kv1.5 and/or Kv1.2 subunits cloned from the RPV and expressed in mammalian cells. (ahajournals.org)
  • Inhibition of calcineurin activity by cyclosporin A resulted in a complete block of Ca 2+ -dependent dephosphorylation of P-sites 4, 5, and 6 and correlated with a prominent increase in ionomycin-evoked glutamate release. (jneurosci.org)
  • In the enrichment culture, 3,4-dihydroxypyridine and its metabolites including formate might be shared as growth substrates and maintain the enrichment culture, including these indispensable strains. (biomedcentral.com)
  • Ethyl 2-aminopyridine-4-carboxylate is an important raw material and intermediate used in organic synthesis, pharmaceuticals, agrochemicals and dyestuff fields. (fishersci.dk)
  • The symptoms started soon after the ingestion of a single pill that was supposed to contain 10 mg 4-AP, but further investigations revealed that each pill had been inadvertently prepared with an 100 mg 4-AP concentration. (hindawi.com)
  • The pill came from a new box of a pharmacy preparation that was supposed to contain 10 mg of 4-aminopyridine per pill. (hindawi.com)
  • Each capsule will contain 10 milligrams of 4-Aminopyridine that will allow to be administered sequentially at progressively higher doses / day. (clinicaltrials.gov)
  • IMSEAR at SEARO: Experimental evaluation of anti-inflammatory activity of 3,4-dimethoxyphenylethylamino-3-aminopyridine (Compound 64-92). (who.int)
  • A single 100 mg 4-AP accidental overdose may cause serious immediate complications, with a slow and incomplete neurological recovery. (hindawi.com)
  • This invention relates a sustained release oral dosage form of an aminopyridine pharmaceutical composition that can be used to treat individuals affected with neurological disorders wherein said pharmaceutical composition maximizes the therapeutic effect, while minimizing adverse side effects. (freepatentsonline.com)
  • The findings of this study (1) indicate that vascular K DR are inhibited by 4-AP via an open-state block mechanism and trapping of the drug within the pore on channel closure and (2) provide novel evidence based on a comparison of functional characteristics that indicate the dominant form of vascular K DR channel complex in RPV involves the heteromultimeric association of Kv1.2 and Kv1.5 subunits. (ahajournals.org)
  • Despite its widespread use, however, the mechanism of block of vascular K DR by 4-AP has not been established conclusively. (ahajournals.org)
  • 12-16 Identification of the mechanism(s) of 4-AP block has been advanced through the study of recombinant Kv channels. (ahajournals.org)
  • If 4-AP blocks the open channel by promoting closure of the activation gate (recent Armstrong-Loboda model), then changes in the leucine heptad repeat that stabilize the channel closed state may contribute to increased 4-AP sensitivity by amplifying the mechanism of 4-AP block. (aspetjournals.org)
  • 4-Aminopyridine is biodegraded in the environment through an unknown mechanism. (biomedcentral.com)
  • Our results demonstrate that in the adult rat hippocampus 4-AP induces in many different regions accumulations of [K + ] 0 in synchrony with the long-lasting field potentials, which are known to correspond to an intracellular long-lasting depolarization of the pyramidal cells. (springer.com)
  • Avoli M, Psarrapoulou C, Tancredi V, Fueta Y (1993) On the synchronous activity induced by 4-aminopyridine in the CA3 subfield of juvenile rat hippocampus. (springer.com)
  • The Effect of 3-, 4-AP and 3,4-DAP on the Evoked Activity of the Pyramidal Cell Layer (CA 1,2) of the Hippocampus. (elsevier.com)
  • The study participant will be interviewed by phone regarding toxicity using the [Common Terminology Criteria for Adverse Events (CTCAE) Version 4.at two different time points (4 weeks, 8 weeks) of each 8-week Treatment Period. (clinicaltrials.gov)
  • The Hanks' solution contained (in mmol/L) NaCl 145, KCl 4.2, KH 2 PO 4 1.2, MgCl 2 1.0, glucose 10, and EGTA 0.1 (pH 7.3). (ahajournals.org)
  • RA Finch, MC Liu, SP Grill, WC Rose, R LoomisTriapine (3-aminopyridine-2-carboxaldehyde-thiosemicarbazone): a potent inhibitor of ribonucleotide reductase activity with broad spectrum antitumor activity. (alfa.com)
  • Moreover, the calcineurin inhibitor cyclosporin A (CsA) prevented the dephosphorylation of P-sites 4, 5, and 6 and facilitated ionomycin-triggered release of glutamate. (jneurosci.org)
  • Phase 4 as portrayed in the diagram shows the resting membrane potential. (ukessays.com)
  • Although improving symptoms, 4-AP does not inhibit progression of MS. Another study, conducted in Brazil, showed that treatment based on fampridine was considered efficient in 70% of the patients. (wikipedia.org)
  • In contrast, Kv1.2 channels displayed a shift in voltage dependence of activation, and this characteristic was also evident during 4-AP treatment when Kv1.2 was coexpressed with Kv1.5 or coupled to Kv1.5 in a tandem construct to produce heterotetrameric [Kv1.5/Kv1.2 channels. (ahajournals.org)
  • A) The numbers of viable cells (mean ± SEM) 24 h after treatment for GC cultures maintained in the absence (CON) of FSH with and without the addition of 2 mM 4-AP (10 culture wells from 5 different GC isolations), and in the presence of FSH with and without the addition of 2 mM 4-AP (8 culture wells from 4 GC isolations). (biomedcentral.com)
  • Aminopyridines have been demonstrated viable for the symptomatic treatment of certain forms of cerebellar ataxia. (eurekaselect.com)
  • Several 2,4-diamino-5-deazapteridine compounds exhibit submicromolar 50% inhibitory concentrations (IC(50)s). (nih.gov)
  • Although we could not isolate strain 4AP-Y on several media, PCR-DGGE analysis and microscopy indicated that the unique bi-polar filamentous bacterial cells gradually became more dominant with increasing 4-aminopyridine concentration in the medium. (biomedcentral.com)
  • In most species, NEBs are located preferentially at or near airway bifurcation, a site ideally suited for sensing changes in airway gas concentration ( 4 ). (pnas.org)
  • Myogenic tone is underpinned by increases in intraluminal pressure depolarizing vascular smooth muscle and increasing the open probability of L-type voltage-dependent Ca 2+ channels (VDCCs) ( 3 , 4 ). (sciencemag.org)
  • In this study, we have investigated variation of the 4-aminopyridine (4-AP)-sensitive current as a function of the size (as measured by the cell capacitance) of SA node cells to elucidate the ionic mechanisms. (ox.ac.uk)
  • 4-Aminopyridine is prepared by the decarbonylation of pyridine-4-carboxamide using sodium hypochlorite via the Hofmann rearrangement. (wikipedia.org)
  • The pyridine carboxamide is generated from the corresponding nitrile, which in turn is obtained from ammoxidation of 4-methylpyridine. (wikipedia.org)
  • Spectroscopic results indicate that sorbed aminopyridine molecules onto loughlinite are coordinated to Lewis acidic centers, zeolitic/bound water molecules, and surface silanol groups by hydrogen bonding interaction through pyridine ring nitrogen lone pairs. (iku.edu.tr)
  • A study has shown that 4-AP is a potent calcium channel activator and can improve synaptic and neuromuscular function by directly acting on the calcium channel beta subunit. (wikipedia.org)
  • 4-AP block of K DR was pulse-frequency dependent, required channel activation, and was associated with a positive shift in voltage dependence of activation. (ahajournals.org)
  • All Phe-for-heptad-Leu substitutions produce gating changes suggesting variable stabilization of the channel closed state conformation, with L1F, L2F, and L5F exhibiting the strongest correlations between altered gating and increased 4-AP sensitivity. (aspetjournals.org)