Periaqueductal Gray
Microinjections
Enkephalin, Methionine
Medulla Oblongata
Receptors, Opioid, mu
Morphine
Escape Reaction
Rats, Sprague-Dawley
Pain
Electroacupuncture
Panic
Analgesics, Opioid
Neurons
Pain Measurement
Brain Stem
Thionins
Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
Enkephalins
Nociceptors
Drug Tolerance
Defense Mechanisms
Raphe Nuclei
Mesencephalon
Narcotics
Proto-Oncogene Proteins c-fos
Opioid Peptides
Naloxone
Brain
Afferent Pathways
Fear
Batrachoidiformes
Neurotensin
Neuroanatomical Tract-Tracing Techniques
Miniature Postsynaptic Potentials
Receptors, Opioid
Rats, Wistar
beta-Endorphin
Inhibitory Postsynaptic Potentials
Pons
Acupuncture Analgesia
Nerve Fibers, Unmyelinated
Dihydroxytryptamines
Bicuculline
Reticular Formation
GABA Agonists
GABA-A Receptor Antagonists
Brain Mapping
Cannabinoid Receptor Modulators
Spinal Cord
Receptor, Cannabinoid, CB1
Hypothalamic Area, Lateral
Mediodorsal Thalamic Nucleus
Endocannabinoids
Magnetic Resonance Imaging
Hypothalamus
Habenula
Enkephalin, D-Penicillamine (2,5)-
Muscimol
Semicarbazides
Cats
GABA Antagonists
Receptors, Opioid, delta
Inhibition by adenosine receptor agonists of synaptic transmission in rat periaqueductal grey neurons. (1/425)
1. The actions of selective adenosine A1 and A2 receptor agonists were examined on synaptic currents in periaqueductal grey (PAG) neurons using patch-clamp recordings in brain slices. 2. The A1 receptor agonist 2-chloro-N-cyclopentyladenosine (CCPA), but not the A2 agonist, 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS21680), inhibited both electrically evoked inhibitory (eIPSCs) and excitatory (eEPSCs) postsynaptic currents. The actions of CCPA were reversed by the A1 receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX). 3. In the absence or presence of forskolin, DPCPX had no effect on eIPSCs, suggesting that concentrations of tonically released adenosine are not sufficient to inhibit synaptic transmission in the PAG. 4. CCPA decreased the frequency of spontaneous miniature action potential-independent IPSCs (mIPSCs) but had no effect on their amplitude distributions. Inhibition persisted in nominally Ca2+-free, high Mg2+ solutions and in 4-aminopyridine. 5. The CCPA-induced decrease in mIPSC frequency was partially blocked by the non-selective protein kinase inhibitor staurosporine, the specific protein kinase A inhibitor 8-para-chlorophenylthioadenosine-3',5'-cyclic monophosphorothioate (Rp-8-CPT-cAMPS), and by 8-bromoadenosine cyclic 3',5' monophosphate (8-Br-cAMP). 6. These results suggest that A1 adenosine receptor agonists inhibit both GABAergic and glutamatergic synaptic transmission in the PAG. Inhibition of GABAergic transmission is mediated by presynaptic mechanisms that partly involve protein kinase A. (+info)Nitric oxide-mediated spinal disinhibition contributes to the sensitization of primate spinothalamic tract neurons. (2/425)
This study concentrated on whether an increase in spinal nitric oxide (NO) diminishes inhibition of spinothalamic tract (STT) cells induced by activating the periaqueductal gray (PAG) or spinal glycinergic and GABAergic receptors, thus contributing to the sensitization of STT neurons. A reduction in inhibition of the responses to cutaneous mechanical stimuli induced by PAG stimulation was seen in wide dynamic range (WDR) STT cells located in the deep layers of the dorsal horn when these neurons were sensitized during administration of a NO donor, 3-morpholinosydnonimine (SIN-1), into the dorsal horn by microdialysis. In contrast, PAG-induced inhibition of the responses of high-threshold (HT) and superficial WDR STT cells was not significantly changed by spinal infusion of SIN-1. A reduction in PAG inhibition when STT cells were sensitized after intradermal injection of capsaicin could be nearly completely blocked by pretreatment of the dorsal horn with a NO synthase inhibitor, 7-nitroindazole. Moreover, spinal inhibition of nociceptive activity of deep WDR STT neurons elicited by iontophoretic release of glycine and GABA agonists was attenuated by administration of SIN-1. This change paralleled the change in PAG-induced inhibition. However, the inhibition of HT and superficial WDR cells induced by glycine and GABA release did not show a significant change when SIN-1 was administered spinally. Combined with our recent results, these data show that the effectiveness of spinal inhibition can be reduced by the NO/cGMP pathway. Thus disinhibition may constitute one mechanism underlying central sensitization. (+info)Periaqueductal gray stimulation-induced inhibition of nociceptive dorsal horn neurons in rats is associated with the release of norepinephrine, serotonin, and amino acids. (3/425)
The stimulation of the periaqueductal gray (PAG) produces behavioral analgesia in rats, cats, monkeys, and humans. This analgesia is believed to be mediated by several neurotransmitter systems, including the serotonergic, noradrenergic, glycinergic, gamma-aminobutyric acidergic, and opiatergic systems. The present study was designed to determine whether PAG stimulation produces the release of serotonin (5-HT), norepinephrine (NE), Gly, and gamma-aminobutyric acid in the spinal cord dorsal horn and whether the release of these neurotransmitters by PAG stimulation is associated with a long-lasting inhibition of the evoked nociceptive responses of dorsal horn neurons. The effect of different frequencies of stimuli on the release of neurotransmitters in the spinal cord was also examined. Microdialysis in combination with HPLC was used to measure the concentrations of neurotransmitters in the lumbar dorsal horn before, during, and after electrical stimulation of the PAG. The PAG was stimulated with electrical pulses at 333 Hz first and then at 67 Hz with the same intensity for 27 min, respectively. Both stimulus frequencies produced a significant increase in the release of 5-HT, NE, Gly, and Asp in the spinal dialysate, but the low-frequency stimulus was more potent in causing the release of neurotransmitters. Low-frequency stimulation also significantly increased the release of Glu. The time course of inhibition of dorsal horn neurons induced by long-lasting PAG stimulation corresponded to the time course of neurotransmitter release. Therefore, the results suggest that the long-lasting inhibition induced by PAG stimulation is mediated in part by the release of 5-HT, NE, and inhibitory amino acids in the spinal cord. (+info)Mu-opioid receptor modulation of calcium channel current in periaqueductal grey neurons from C57B16/J mice and mutant mice lacking MOR-1. (4/425)
1. The actions of opioid receptor agonists on the calcium channel currents (IBa) of acutely dissociated periaqueductal grey (PAG) neurons from C57B16/J mice and mutant mice lacking the first exon of the mu-opioid receptor (MOR-1) were examined using whole cell patch clamp techniques. These effects were compared with the GABA(B)-receptor agonist baclofen. 2. The endogenous opioid agonist methionine-enkephalin (met-enkephalin, pEC50 6.8, maximum inhibition 40%), the putative endogenous mu-opioid agonist endomorphin-1 (pEC50 6.2, maximum inhibition 35%) and the mu-opioid selective agonist DAMGO (Tyr-D-Ala-Gly-N-Me-Phe-Gly-ol enkephalin, pEC50 6.9, maximum inhibition 40%) inhibited IBa in 70% of mouse PAG neurons. The inhibition of IBa by each agonist was completely prevented by the mu-receptor antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2). The delta-opioid receptor agonists DPDPE ([D-Pen2,5]enkephalin, 1 microM) and deltorphin II (1 microM), and the kappa-opioid receptor agonist U-69593 (1-10 microM), did not affect IBa in any cell tested. 3. The GABA(B) agonist baclofen inhibited IBa in all neurons (pEC50 5.9, maximum inhibition 42%). 4. In neurons from the MOR-1 deficient mice, the mu-opioid agonists met-enkephalin, DAMGO and endomorphin-1 did not inhibit IBa, whilst baclofen inhibited IBa in a manner indistinguishable from wild type mice. 5. A maximally effective concentration of endomorphin-1 (30 microM) partially (19%), but significantly (P<0.005), occluded the inhibition of IBa normally elicited by a maximally effective concentration of met-enkephalin (10 microM). 6. This study indicates that mu-opioid receptors, but not delta- or kappa-opioid receptors, modulate somatic calcium channel currents in mouse PAG neurons. The putative endogenous mu-agonist, endomorphin-1, was a partial agonist in mouse PAG neurons. (+info)Mechanism underlying increased neuronal activity in the rat ventrolateral periaqueductal grey by a mu-opioid. (5/425)
1. The overall effect of the mu-opioid receptor agonist DAMGO (Tyr-D-Ala-Gly-MePhe-Gly-ol) on ventrolateral periaqueductal grey (PAG) neurons in brain slices was studied using the whole-cell patch-clamp recording technique. 2. Under current-clamp conditions, DAMGO (1 microM) increased cell firing in many PAG neurons even though the opioid induced hyperpolarization and inhibited excitatory postsynaptic potentials (EPSPs) in these cells. 3. The increase in cell activity by DAMGO was observed in both transverse and horizontal slices. The increase persisted when the membrane potential was re-depolarized to the control level. Thus, different planes of sections or the removal of Na+ channel inactivation could not account for the observation. 4. The GABA antagonist bicuculline caused cell firing, mimicking the excitatory effect of DAMGO. Unlike DAMGO, however, bicuculline depolarized PAG cells. 5. Under voltage-clamp conditions, with the same driving force, the evoked inhibitory postsynaptic currents (IPSCs) in these neurons were 2.3 times larger than the evoked excitatory postsynaptic currents (EPSCs). Furthermore, DAMGO inhibited IPSCs by 60.7% while it inhibited EPSCs by 35.3%. 6. We propose that the overall effect of an opioid depends on the dynamic balance of its excitatory and inhibitory actions. In the PAG, the blockade of the inhibitory drive of GABAergic inputs by DAMGO is large. It overcomes the DAMGO-induced hyperpolarization and inhibition of EPSCs and thus results in the excitation of these neurons. (+info)Modulation of intrathecal morphine-induced immunosuppression by microinjection of naloxone into periaqueductal gray. (6/425)
AIM: To study the involvement of opioid receptor of periaqueductal gray (PAG) and hypothalamic-pituitary-adrenal (HPA) axis in the effect of intrathecal morphine on immune function. METHODS: Rat splenic natural killer (NK) cell activity was determined by a europium release assay; the concanavalin A-induced splenic IL-2 production, TNF-beta activity, and serum TNF-alpha level were determined by colorimetric thiazolyl blue tetrazolium bromide (MTT) and gentian violet assay, and serum corticotrophin (ACTH) level by radio-immunological method after intrathecal injection of morphine and PAG microinjection of naloxone. RESULTS: Intrathecal morphine inhibited splenic NK cell activity, IL-2 production, TNF-beta activity, and increased in serum ACTH level. Microinjection of naloxone 1 microgram into PAG partially antagonized the inhibition of NK cell activity and the elevation of serum ACTH level by morphine. CONCLUSION: The opioid receptor of PAG involved in the suppression of NK cell activity by intrathecal morphine, which was accompanied by an activation of HPA axis. (+info)Differential patterns of spinal sympathetic outflow involving a 10-Hz rhythm. (7/425)
Time and frequency domain analyses were used to examine the changes in the relationships between the discharges of the inferior cardiac (CN) and vertebral (VN) postganglionic sympathetic nerves produced by electrical activation of the midbrain periaqueductal gray (PAG) in urethan-anesthetized, baroreceptor-denervated cats. CN-VN coherence and phase angle in the 10-Hz band served as measures of the coupling of the central oscillators controlling these nerves. The 10-Hz rhythm in CN and VN discharges was entrained 1:1 to electrical stimuli applied to the PAG at frequencies between 7 and 12 Hz. CN 10-Hz discharges were increased, and VN 10-Hz discharges were decreased when the frequency of PAG stimulation was equal to or above that of the free-running rhythm. In contrast, stimulation of the same PAG sites at lower frequencies increased, albeit disproportionately, the 10-Hz discharges of both nerves. In either case, PAG stimulation significantly increased the phase angle between the two signals (VN 10-Hz activity lagged CN activity); coherence values relating their discharges were little affected. However, the increase in phase angle was significantly more pronounced when the 10-Hz discharges of the two nerves were reciprocally affected. Importantly, partialization of the phase spectrum using the PAG stimuli did not reverse the change in CN-VN phase angle. This observation suggests that the increase in the CN-VN phase angle reflected changes in the phase relations between coupled oscillators in the brain stem rather than the difference in conduction times to the two nerves from the site of PAG stimulation. In contrast to the effects elicited by PAG stimulation, stimulation of the medullary lateral tegmental field induced uniform increases in the 10-Hz discharges of the two nerves and no change in the CN-VN phase angle. Our results demonstrate that changes in the phase relations among coupled brain stem 10-Hz oscillators are accompanied by differential patterns of spinal sympathetic outflow. The reciprocal changes in CN and VN discharges produced by PAG stimulation are consistent with the pattern of spinal sympathetic outflow expected during the defense reaction. (+info)Fluorescent double-label study of lateral reticular nucleus projections to the spinal cord and periaqueductal gray in the rat. (8/425)
Following injections of WGA-HRP into either the spinal cord or periaqueductal gray, labeled neurons were observed bilaterally along the periphery of the lateral reticular nucleus (LRN) magnocellular division. The possibility that some of these neurons in the LRN provide collateral axonal branches to both the periaqueductal gray and the spinal cord was investigated in rats using a retrograde double-labeling method employing two different fluorescent tracers, True Blue and Nuclear Yellow. Following sequential injection of the two fluorescent axonal tracers into the spinal cord and periaqueductal gray in the same animal, a modest number of double-labeled neurons were observed bilaterally near the medial and dorsal perimeter of the magnocellular division of the LRN. The labeled neurons were distinctly multipolar in shape and measured approximately 15-18 mu in their greatest transverse diameter. No double-labeled neurons were observed in the parvocellular or subtrigeminal divisions of the LRN. Based upon these observations, it is suggested that collaterals of the LRN-spinal pathway provide feedback information to the periaqueductal gray that might then be used to modulate the participation of the latter cell group in a variety of pain processing and cardiovascular regulatory functions. (+info)The periaqueductal gray (PAG) is a region in the midbrain, surrounding the cerebral aqueduct (a narrow channel connecting the third and fourth ventricles within the brain). It is a column of neurons that plays a crucial role in the modulation of pain perception, cardiorespiratory regulation, and defensive behaviors. The PAG is involved in the descending pain modulatory system, where it receives input from various emotional and cognitive areas and sends output to the rostral ventromedial medulla, which in turn regulates nociceptive processing at the spinal cord level. Additionally, the PAG is implicated in the regulation of fear, anxiety, and stress responses, as well as sexual behavior and reward processing.
Microinjection is a medical technique that involves the use of a fine, precise needle to inject small amounts of liquid or chemicals into microscopic structures, cells, or tissues. This procedure is often used in research settings to introduce specific substances into individual cells for study purposes, such as introducing DNA or RNA into cell nuclei to manipulate gene expression.
In clinical settings, microinjections may be used in various medical and cosmetic procedures, including:
1. Intracytoplasmic Sperm Injection (ICSI): A type of assisted reproductive technology where a single sperm is injected directly into an egg to increase the chances of fertilization during in vitro fertilization (IVF) treatments.
2. Botulinum Toxin Injections: Microinjections of botulinum toxin (Botox, Dysport, or Xeomin) are used for cosmetic purposes to reduce wrinkles and fine lines by temporarily paralyzing the muscles responsible for their formation. They can also be used medically to treat various neuromuscular disorders, such as migraines, muscle spasticity, and excessive sweating (hyperhidrosis).
3. Drug Delivery: Microinjections may be used to deliver drugs directly into specific tissues or organs, bypassing the systemic circulation and potentially reducing side effects. This technique can be particularly useful in treating localized pain, delivering growth factors for tissue regeneration, or administering chemotherapy agents directly into tumors.
4. Gene Therapy: Microinjections of genetic material (DNA or RNA) can be used to introduce therapeutic genes into cells to treat various genetic disorders or diseases, such as cystic fibrosis, hemophilia, or cancer.
Overall, microinjection is a highly specialized and precise technique that allows for the targeted delivery of substances into small structures, cells, or tissues, with potential applications in research, medical diagnostics, and therapeutic interventions.
Enkephalins are naturally occurring opioid peptides in the body that bind to opiate receptors and help reduce pain and produce a sense of well-being. There are two major types of enkephalins: Leu-enkephalin and Met-enkephalin, which differ by only one amino acid at the N-terminus.
Methionine-enkephalin (Met-enkephalin) is a type of enkephalin that contains methionine as its N-terminal amino acid. Its chemical formula is Tyr-Gly-Gly-Phe-Met, and it is derived from the precursor protein proenkephalin. Met-enkephalin has a shorter half-life than Leu-enkephalin due to its susceptibility to enzymatic degradation by aminopeptidases.
Met-enkephalin plays an essential role in pain modulation, reward processing, and addiction. It is also involved in various physiological functions, including respiration, cardiovascular regulation, and gastrointestinal motility. Dysregulation of enkephalins has been implicated in several pathological conditions, such as chronic pain, drug addiction, and neurodegenerative disorders.
The medulla oblongata is a part of the brainstem that is located in the posterior portion of the brainstem and continues with the spinal cord. It plays a vital role in controlling several critical bodily functions, such as breathing, heart rate, and blood pressure. The medulla oblongata also contains nerve pathways that transmit sensory information from the body to the brain and motor commands from the brain to the muscles. Additionally, it is responsible for reflexes such as vomiting, swallowing, coughing, and sneezing.
Opioid mu receptors, also known as mu-opioid receptors (MORs), are a type of G protein-coupled receptor that binds to opioids, a class of chemicals that include both natural and synthetic painkillers. These receptors are found in the brain, spinal cord, and gastrointestinal tract, and play a key role in mediating the effects of opioid drugs such as morphine, heroin, and oxycodone.
MORs are involved in pain modulation, reward processing, respiratory depression, and physical dependence. Activation of MORs can lead to feelings of euphoria, decreased perception of pain, and slowed breathing. Prolonged activation of these receptors can also result in tolerance, where higher doses of the drug are required to achieve the same effect, and dependence, where withdrawal symptoms occur when the drug is discontinued.
MORs have three main subtypes: MOR-1, MOR-2, and MOR-3, with MOR-1 being the most widely studied and clinically relevant. Selective agonists for MOR-1, such as fentanyl and sufentanil, are commonly used in anesthesia and pain management. However, the abuse potential and risk of overdose associated with these drugs make them a significant public health concern.
Morphine is a potent opioid analgesic (pain reliever) derived from the opium poppy. It works by binding to opioid receptors in the brain and spinal cord, blocking the transmission of pain signals and reducing the perception of pain. Morphine is used to treat moderate to severe pain, including pain associated with cancer, myocardial infarction, and other conditions. It can also be used as a sedative and cough suppressant.
Morphine has a high potential for abuse and dependence, and its use should be closely monitored by healthcare professionals. Common side effects of morphine include drowsiness, respiratory depression, constipation, nausea, and vomiting. Overdose can result in respiratory failure, coma, and death.
An "escape reaction" is a behavioral response displayed by an organism when it attempts to escape from a harmful, noxious, or stressful stimulus or situation. This response is typically characterized by rapid and directed movement away from the source of discomfort or danger. It is a fundamental survival mechanism that is observed across many species, including humans.
In a medical context, an escape reaction may be observed in response to painful medical procedures or treatments. For example, a patient may try to move or pull away during an injection or other invasive procedure. Healthcare providers must be aware of and prepared to manage escape reactions to ensure the safety and comfort of their patients during medical procedures.
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.
Neural pathways, also known as nerve tracts or fasciculi, refer to the highly organized and specialized routes through which nerve impulses travel within the nervous system. These pathways are formed by groups of neurons (nerve cells) that are connected in a series, creating a continuous communication network for electrical signals to transmit information between different regions of the brain, spinal cord, and peripheral nerves.
Neural pathways can be classified into two main types: sensory (afferent) and motor (efferent). Sensory neural pathways carry sensory information from various receptors in the body (such as those for touch, temperature, pain, and vision) to the brain for processing. Motor neural pathways, on the other hand, transmit signals from the brain to the muscles and glands, controlling movements and other effector functions.
The formation of these neural pathways is crucial for normal nervous system function, as it enables efficient communication between different parts of the body and allows for complex behaviors, cognitive processes, and adaptive responses to internal and external stimuli.
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. It is a complex phenomenon that can result from various stimuli, such as thermal, mechanical, or chemical irritation, and it can be acute or chronic. The perception of pain involves the activation of specialized nerve cells called nociceptors, which transmit signals to the brain via the spinal cord. These signals are then processed in different regions of the brain, leading to the conscious experience of pain. It's important to note that pain is a highly individual and subjective experience, and its perception can vary widely among individuals.
Electroacupuncture is a form of acupuncture where a small electric current is passed between pairs of acupuncture needles. This technique is used to stimulate the acupoints more strongly and consistently than with manual acupuncture. The intensity of the electrical impulses can be adjusted depending on the patient's comfort level and the desired therapeutic effect. Electroacupuncture is often used to treat conditions such as chronic pain, muscle spasms, and paralysis. It may also be used in the treatment of addiction, weight loss, and stroke rehabilitation.
Panic, in a medical context, refers to an intense and sudden episode of fear or discomfort that reaches a peak within minutes, accompanied by physical reactions such as increased heart rate, rapid breathing (hyperventilation), trembling, shaking, and potentially causing a feeling of losing control or going crazy. It's often a symptom of panic disorder or another anxiety disorder. A single panic attack doesn't necessarily mean a person has a panic disorder, but repeated attacks may indicate this condition.
Analgesia is defined as the absence or relief of pain in a patient, achieved through various medical means. It is derived from the Greek word "an-" meaning without and "algein" meaning to feel pain. Analgesics are medications that are used to reduce pain without causing loss of consciousness, and they work by blocking the transmission of pain signals to the brain.
Examples of analgesics include over-the-counter medications such as acetaminophen (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin) and naproxen (Aleve). Prescription opioid painkillers, such as oxycodone (OxyContin, Percocet) and hydrocodone (Vicodin), are also used for pain relief but carry a higher risk of addiction and abuse.
Analgesia can also be achieved through non-pharmacological means, such as through nerve blocks, spinal cord stimulation, acupuncture, and other complementary therapies. The choice of analgesic therapy depends on the type and severity of pain, as well as the patient's medical history and individual needs.
Analgesics, opioid are a class of drugs used for the treatment of pain. They work by binding to specific receptors in the brain and spinal cord, blocking the transmission of pain signals to the brain. Opioids can be synthetic or natural, and include drugs such as morphine, codeine, oxycodone, hydrocodone, hydromorphone, fentanyl, and methadone. They are often used for moderate to severe pain, such as that resulting from injury, surgery, or chronic conditions like cancer. However, opioids can also produce euphoria, physical dependence, and addiction, so they are tightly regulated and carry a risk of misuse.
Neurons, also known as nerve cells or neurocytes, are specialized cells that constitute the basic unit of the nervous system. They are responsible for receiving, processing, and transmitting information and signals within the body. Neurons have three main parts: the dendrites, the cell body (soma), and the axon. The dendrites receive signals from other neurons or sensory receptors, while the axon transmits these signals to other neurons, muscles, or glands. The junction between two neurons is called a synapse, where neurotransmitters are released to transmit the signal across the gap (synaptic cleft) to the next neuron. Neurons vary in size, shape, and structure depending on their function and location within the nervous system.
Pain measurement, in a medical context, refers to the quantification or evaluation of the intensity and/or unpleasantness of a patient's subjective pain experience. This is typically accomplished through the use of standardized self-report measures such as numerical rating scales (NRS), visual analog scales (VAS), or categorical scales (mild, moderate, severe). In some cases, physiological measures like heart rate, blood pressure, and facial expressions may also be used to supplement self-reported pain ratings. The goal of pain measurement is to help healthcare providers better understand the nature and severity of a patient's pain in order to develop an effective treatment plan.
The brainstem is the lower part of the brain that connects to the spinal cord. It consists of the midbrain, pons, and medulla oblongata. The brainstem controls many vital functions such as heart rate, breathing, and blood pressure. It also serves as a relay center for sensory and motor information between the cerebral cortex and the rest of the body. Additionally, several cranial nerves originate from the brainstem, including those that control eye movements, facial movements, and hearing.
Thionins are a group of small, sulfur-rich, cysteine-rich proteins that are widely distributed in nature, particularly in seeds of various plants. They have been found in over 60 plant species and are known for their antimicrobial properties. Thionins are toxic to a wide range of organisms, including bacteria, fungi, and insects.
The name "thionin" comes from the high sulfur content of these proteins, which is reflected in their chemical structure. Thionins contain eight cysteine residues that form four disulfide bonds, giving them a stable and rigid structure. This structural feature allows thionins to maintain their activity under a wide range of conditions, including extreme temperatures and pH levels.
Thionins have been studied for their potential use as natural pesticides and antimicrobial agents in agriculture and medicine. However, their toxicity to non-target organisms, including mammals, has limited their practical application. Further research is needed to fully understand the mechanisms of thionin toxicity and to develop strategies for harnessing their potential benefits while minimizing their risks.
Enkephalins are naturally occurring opioid peptides that bind to opiate receptors in the brain and other organs, producing pain-relieving and other effects. They are derived from the precursor protein proenkephalin and consist of two main types: Leu-enkephalin and Met-enkephalin. Enkephalins play a role in pain modulation, stress response, mood regulation, and addictive behaviors. They are also involved in the body's reward system and have been implicated in various physiological processes such as respiration, gastrointestinal motility, and hormone release.
Nociceptors are specialized peripheral sensory neurons that detect and transmit signals indicating potentially harmful stimuli in the form of pain. They are activated by various noxious stimuli such as extreme temperatures, intense pressure, or chemical irritants. Once activated, nociceptors transmit these signals to the central nervous system (spinal cord and brain) where they are interpreted as painful sensations, leading to protective responses like withdrawing from the harmful stimulus or seeking medical attention. Nociceptors play a crucial role in our perception of pain and help protect the body from further harm.
Drug tolerance is a medical concept that refers to the decreased response to a drug following its repeated use, requiring higher doses to achieve the same effect. This occurs because the body adapts to the presence of the drug, leading to changes in the function or expression of targets that the drug acts upon, such as receptors or enzymes. Tolerance can develop to various types of drugs, including opioids, benzodiazepines, and alcohol, and it is often associated with physical dependence and addiction. It's important to note that tolerance is different from resistance, which refers to the ability of a pathogen to survive or grow in the presence of a drug, such as antibiotics.
Electronarcosis is a term that refers to the use of high-frequency electric currents to induce a state of unconsciousness or narcosis. It was an experimental medical procedure that was studied in the early 20th century as a possible method for surgical anesthesia. However, it is no longer in use today due to the development of safer and more effective anesthetic drugs.
During electronarcosis, electrodes were placed on the patient's skin, and a high-frequency alternating current was passed through the body. The current would cause a loss of consciousness by interfering with the electrical activity of the brain. However, this method of anesthesia had several drawbacks, including the risk of burns, muscle contractions, and other injuries caused by the electric current.
While electronarcosis is not used in modern medicine, high-frequency electrical stimulation is still used in some medical treatments, such as transcutaneous electrical nerve stimulation (TENS) for pain relief and electromagnetic brain stimulation for the treatment of depression and other mental health disorders.
Defense mechanisms are unconscious psychological strategies that individuals use to cope with stressful, threatening, or uncomfortable situations. These mechanisms help protect the ego from being overwhelmed by anxiety, fear, or other negative emotions. They can also help individuals maintain a positive self-image and a sense of control in difficult circumstances.
There are many different types of defense mechanisms, including:
1. Repression: The unconscious forgetting or pushing aside of painful memories or thoughts.
2. Denial: Refusing to acknowledge the existence or reality of a threatening situation or feeling.
3. Projection: Attributing one's own unacceptable thoughts or emotions to someone else.
4. Displacement: Channeling unacceptable feelings toward a safer or less threatening target.
5. Rationalization: Creating logical explanations or excuses for unacceptable behavior or feelings.
6. Reaction formation: Converting unconscious impulses or desires into their opposite, conscious attitudes or behaviors.
7. Sublimation: Transforming unacceptable impulses or instincts into socially acceptable behaviors or activities.
8. Regression: Returning to an earlier stage of development in order to cope with stress or anxiety.
9. Suppression: Consciously pushing aside unwanted thoughts or feelings.
10. Identification: Adopting the characteristics, attitudes, or behaviors of another person as a way of coping with anxiety or fear.
Defense mechanisms can be adaptive or maladaptive, depending on the situation and how they are used. While they can help individuals cope with stress and maintain their emotional well-being in the short term, relying too heavily on defense mechanisms can lead to problems in relationships, work, and other areas of life. It is important for individuals to be aware of their defense mechanisms and work to develop healthier coping strategies over time.
The Raphe Nuclei are clusters of neurons located in the brainstem, specifically in the midline of the pons, medulla oblongata, and mesencephalon (midbrain). These neurons are characterized by their ability to synthesize and release serotonin, a neurotransmitter that plays a crucial role in regulating various functions such as mood, appetite, sleep, and pain perception.
The Raphe Nuclei project axons widely throughout the central nervous system, allowing serotonin to modulate the activity of other neurons. There are several subdivisions within the Raphe Nuclei, each with distinct connections and functions. Dysfunction in the Raphe Nuclei has been implicated in several neurological and psychiatric disorders, including depression, anxiety, and chronic pain.
The mesencephalon, also known as the midbrain, is the middle portion of the brainstem that connects the hindbrain (rhombencephalon) and the forebrain (prosencephalon). It plays a crucial role in several important functions including motor control, vision, hearing, and the regulation of consciousness and sleep-wake cycles. The mesencephalon contains several important structures such as the cerebral aqueduct, tectum, tegmentum, cerebral peduncles, and several cranial nerve nuclei (III and IV).
Narcotics, in a medical context, are substances that induce sleep, relieve pain, and suppress cough. They are often used for anesthesia during surgical procedures. Narcotics are derived from opium or its synthetic substitutes and include drugs such as morphine, codeine, fentanyl, oxycodone, and hydrocodone. These drugs bind to specific receptors in the brain and spinal cord, reducing the perception of pain and producing a sense of well-being. However, narcotics can also produce physical dependence and addiction, and their long-term use can lead to tolerance, meaning that higher doses are required to achieve the same effect. Narcotics are classified as controlled substances due to their potential for abuse and are subject to strict regulations.
Proto-oncogene proteins, such as c-Fos, are normal cellular proteins that play crucial roles in various biological processes including cell growth, differentiation, and survival. They can be activated or overexpressed due to genetic alterations, leading to the formation of cancerous cells. The c-Fos protein is a nuclear phosphoprotein involved in signal transduction pathways and forms a heterodimer with c-Jun to create the activator protein-1 (AP-1) transcription factor complex. This complex binds to specific DNA sequences, thereby regulating the expression of target genes that contribute to various cellular responses, including proliferation, differentiation, and apoptosis. Dysregulation of c-Fos can result in uncontrolled cell growth and malignant transformation, contributing to tumor development and progression.
Opioid peptides are naturally occurring short chains of amino acids in the body that bind to opioid receptors in the brain, spinal cord, and gut, acting in a similar way to opiate drugs like morphine or heroin. They play crucial roles in pain regulation, reward systems, and addictive behaviors. Some examples of opioid peptides include endorphins, enkephalins, and dynorphins. These substances are released in response to stress, physical exertion, or injury and help modulate the perception of pain and produce feelings of pleasure or euphoria.
In medical terms, "rage" is not a diagnosis or a specific medical condition. However, it may be used to describe a symptom of certain medical conditions, such as intermittent explosive disorder (IED) or certain types of dementia. In IED, "rage" refers to recurrent, sudden episodes of uncontrolled anger and aggression that are out of proportion to the situation. In dementia, "sundowning" or "late-day confusion" can lead to increased agitation, confusion, and sometimes aggressive behavior in the late afternoon and early evening. It is important to consult with a healthcare professional for proper evaluation and diagnosis if experiencing issues related to anger or behavior.
Naloxone is a medication used to reverse the effects of opioids, both illicit and prescription. It works by blocking the action of opioids on the brain and restoring breathing in cases where opioids have caused depressed respirations. Common brand names for naloxone include Narcan and Evzio.
Naloxone is an opioid antagonist, meaning that it binds to opioid receptors in the body without activating them, effectively blocking the effects of opioids already present at these sites. It has no effect in people who have not taken opioids and does not reverse the effects of other sedatives or substances.
Naloxone can be administered via intranasal, intramuscular, intravenous, or subcutaneous routes. The onset of action varies depending on the route of administration but generally ranges from 1 to 5 minutes when given intravenously and up to 10-15 minutes with other methods.
The duration of naloxone's effects is usually shorter than that of most opioids, so multiple doses or a continuous infusion may be necessary in severe cases to maintain reversal of opioid toxicity. Naloxone has been used successfully in emergency situations to treat opioid overdoses and has saved many lives.
It is important to note that naloxone does not reverse the effects of other substances or address the underlying causes of addiction, so it should be used as part of a comprehensive treatment plan for individuals struggling with opioid use disorders.
Pain threshold is a term used in medicine and research to describe the point at which a stimulus begins to be perceived as painful. It is an individual's subjective response and can vary from person to person based on factors such as their pain tolerance, mood, expectations, and cultural background.
The pain threshold is typically determined through a series of tests where gradually increasing levels of stimuli are applied until the individual reports feeling pain. This is often used in research settings to study pain perception and analgesic efficacy. However, it's important to note that the pain threshold should not be confused with pain tolerance, which refers to the maximum level of pain a person can endure.
The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:
1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.
The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.
Afferent pathways, also known as sensory pathways, refer to the neural connections that transmit sensory information from the peripheral nervous system to the central nervous system (CNS), specifically to the brain and spinal cord. These pathways are responsible for carrying various types of sensory information, such as touch, temperature, pain, pressure, vibration, hearing, vision, and taste, to the CNS for processing and interpretation.
The afferent pathways begin with sensory receptors located throughout the body, which detect changes in the environment and convert them into electrical signals. These signals are then transmitted via afferent neurons, also known as sensory neurons, to the spinal cord or brainstem. Within the CNS, the information is further processed and integrated with other neural inputs before being relayed to higher cognitive centers for conscious awareness and response.
Understanding the anatomy and physiology of afferent pathways is essential for diagnosing and treating various neurological conditions that affect sensory function, such as neuropathies, spinal cord injuries, and brain disorders.
Fear is a basic human emotion that is typically characterized by a strong feeling of anxiety, apprehension, or distress in response to a perceived threat or danger. It is a natural and adaptive response that helps individuals identify and respond to potential dangers in their environment, and it can manifest as physical, emotional, and cognitive symptoms.
Physical symptoms of fear may include increased heart rate, rapid breathing, sweating, trembling, and muscle tension. Emotional symptoms may include feelings of anxiety, worry, or panic, while cognitive symptoms may include difficulty concentrating, racing thoughts, and intrusive thoughts about the perceived threat.
Fear can be a normal and adaptive response to real dangers, but it can also become excessive or irrational in some cases, leading to phobias, anxiety disorders, and other mental health conditions. In these cases, professional help may be necessary to manage and overcome the fear.
Batrachoidiformes is an order of primarily marine ray-finned fish that includes the genera Batrachoides, Halophryne, Porichthys, and Thalassophryne. These fish are characterized by having a stout body, large head, and strong, bony mouthparts. They are often called "toadfish" due to their warty skin and toad-like appearance. Some species have the ability to produce sounds, which they use for communication and mating. They are found in tropical and subtropical waters of the Atlantic and Pacific Oceans, as well as in the Mediterranean Sea.
Narcotic antagonists are a class of medications that block the effects of opioids, a type of narcotic pain reliever, by binding to opioid receptors in the brain and blocking the activation of these receptors by opioids. This results in the prevention or reversal of opioid-induced effects such as respiratory depression, sedation, and euphoria. Narcotic antagonists are used for a variety of medical purposes, including the treatment of opioid overdose, the management of opioid dependence, and the prevention of opioid-induced side effects in certain clinical situations. Examples of narcotic antagonists include naloxone, naltrexone, and methylnaltrexone.
Neurotensin is a neuropeptide that is widely distributed in the central nervous system and the gastrointestinal tract. It is composed of 13 amino acids and plays a role as a neurotransmitter or neuromodulator in various physiological functions, including pain regulation, temperature regulation, and feeding behavior. Neurotensin also has been shown to have potential roles in the development of certain diseases such as cancer and neurological disorders. It exerts its effects by binding to specific receptors, known as neurotensin receptors (NTSR1, NTSR2, and NTSR3), which are widely distributed throughout the body.
Neuroanatomical tract-tracing techniques are a set of neuroanatomical methods used to map the connections and pathways between different neurons, neural nuclei, or brain regions. These techniques involve introducing a tracer substance into a specific population of neurons, which is then transported through the axons and dendrites to other connected cells. The distribution of the tracer can be visualized and analyzed to determine the pattern of connectivity between different brain areas.
There are two main types of neuroanatomical tract-tracing techniques: anterograde and retrograde. Anterograde tracing involves introducing a tracer into the cell body or dendrites of a neuron, which is then transported to the axon terminals in target areas. Retrograde tracing, on the other hand, involves introducing a tracer into the axon terminals of a neuron, which is then transported back to the cell body and dendrites.
Examples of neuroanatomical tract-tracing techniques include the use of horseradish peroxidase (HRP), fluorescent tracers, radioactive tracers, and viral vectors. These techniques have been instrumental in advancing our understanding of brain circuitry and function, and continue to be an important tool in neuroscience research.
Miniature postsynaptic potentials (mPSPs) are small electrical signals that occur in the postsynaptic neuron at a chemical synapse. They are caused by the random release of a single vesicle of neurotransmitters from the presynaptic neuron, even when there is no action potential or nerve impulse.
mPSPs are typically too small to trigger an action potential on their own, but they can contribute to the overall excitability of the postsynaptic neuron and influence its likelihood of firing an action potential in response to subsequent stimuli. The amplitude of mPSPs is influenced by several factors, including the number and location of receptors on the postsynaptic membrane, the concentration of neurotransmitters released, and the distance between the presynaptic and postsynaptic neurons.
mPSPs are an important tool for studying synaptic transmission and plasticity, as they provide a way to measure the strength and reliability of individual synapses in isolation from other inputs. They have also been implicated in various physiological processes, such as learning and memory, and may play a role in neurological disorders that affect synaptic function.
Opioid receptors are a type of G protein-coupled receptor (GPCR) found in the cell membranes of certain neurons in the central and peripheral nervous system. They bind to opioids, which are chemicals that can block pain signals and produce a sense of well-being. There are four main types of opioid receptors: mu, delta, kappa, and nociceptin. These receptors play a role in the regulation of pain, reward, addiction, and other physiological functions. Activation of opioid receptors can lead to both therapeutic effects (such as pain relief) and adverse effects (such as respiratory depression and constipation).
'Animal behavior' refers to the actions or responses of animals to various stimuli, including their interactions with the environment and other individuals. It is the study of the actions of animals, whether they are instinctual, learned, or a combination of both. Animal behavior includes communication, mating, foraging, predator avoidance, and social organization, among other things. The scientific study of animal behavior is called ethology. This field seeks to understand the evolutionary basis for behaviors as well as their physiological and psychological mechanisms.
Analgesics are a class of drugs that are used to relieve pain. They work by blocking the transmission of pain signals in the nervous system, allowing individuals to manage their pain levels more effectively. There are many different types of analgesics available, including both prescription and over-the-counter options. Some common examples include acetaminophen (Tylenol), ibuprofen (Advil or Motrin), and opioids such as morphine or oxycodone.
The choice of analgesic will depend on several factors, including the type and severity of pain being experienced, any underlying medical conditions, potential drug interactions, and individual patient preferences. It is important to use these medications as directed by a healthcare provider, as misuse or overuse can lead to serious side effects and potential addiction.
In addition to their pain-relieving properties, some analgesics may also have additional benefits such as reducing inflammation (like in the case of nonsteroidal anti-inflammatory drugs or NSAIDs) or causing sedation (as with certain opioids). However, it is essential to weigh these potential benefits against the risks and side effects associated with each medication.
When used appropriately, analgesics can significantly improve a person's quality of life by helping them manage their pain effectively and allowing them to engage in daily activities more comfortably.
Gamma-Aminobutyric Acid (GABA) is a major inhibitory neurotransmitter in the mammalian central nervous system. It plays a crucial role in regulating neuronal excitability and preventing excessive neuronal firing, which helps to maintain neural homeostasis and reduce the risk of seizures. GABA functions by binding to specific receptors (GABA-A, GABA-B, and GABA-C) on the postsynaptic membrane, leading to hyperpolarization of the neuronal membrane and reduced neurotransmitter release from presynaptic terminals.
In addition to its role in the central nervous system, GABA has also been identified as a neurotransmitter in the peripheral nervous system, where it is involved in regulating various physiological processes such as muscle relaxation, hormone secretion, and immune function.
GABA can be synthesized in neurons from glutamate, an excitatory neurotransmitter, through the action of the enzyme glutamic acid decarboxylase (GAD). Once synthesized, GABA is stored in synaptic vesicles and released into the synapse upon neuronal activation. After release, GABA can be taken up by surrounding glial cells or degraded by the enzyme GABA transaminase (GABA-T) into succinic semialdehyde, which is further metabolized to form succinate and enter the Krebs cycle for energy production.
Dysregulation of GABAergic neurotransmission has been implicated in various neurological and psychiatric disorders, including epilepsy, anxiety, depression, and sleep disturbances. Therefore, modulating GABAergic signaling through pharmacological interventions or other therapeutic approaches may offer potential benefits for the treatment of these conditions.
Pain perception refers to the neural and psychological processes involved in receiving, interpreting, and responding to painful stimuli. It is the subjective experience of pain, which can vary greatly among individuals due to factors such as genetics, mood, expectations, and past experiences. The perception of pain involves complex interactions between the peripheral nervous system (which detects and transmits information about tissue damage or potential harm), the spinal cord (where this information is processed and integrated with other sensory inputs), and the brain (where the final interpretation and emotional response to pain occurs).
"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.
Beta-endorphins are naturally occurring opioid peptides that are produced in the brain and other parts of the body. They are synthesized from a larger precursor protein called proopiomelanocortin (POMC) and consist of 31 amino acids. Beta-endorphins have potent analgesic effects, which means they can reduce the perception of pain. They also play a role in regulating mood, emotions, and various physiological processes such as immune function and hormonal regulation.
Beta-endorphins bind to opioid receptors in the brain and other tissues, leading to a range of effects including pain relief, sedation, euphoria, and reduced anxiety. They are released in response to stress, physical activity, and certain physiological conditions such as pregnancy and lactation. Beta-endorphins have been studied for their potential therapeutic uses in the treatment of pain, addiction, and mood disorders. However, more research is needed to fully understand their mechanisms of action and potential side effects.
Inhibitory postsynaptic potentials (IPSPs) are electrical signals that occur in the postsynaptic neuron when an inhibitory neurotransmitter is released from the presynaptic neuron and binds to receptors on the postsynaptic membrane. This binding causes a decrease in the excitability of the postsynaptic neuron, making it less likely to fire an action potential.
IPSPs are typically caused by neurotransmitters such as gamma-aminobutyric acid (GABA) and glycine, which open chloride channels in the postsynaptic membrane. The influx of negatively charged chloride ions into the neuron causes a hyperpolarization of the membrane potential, making it more difficult for the neuron to reach the threshold needed to generate an action potential.
IPSPs play an important role in regulating the activity of neural circuits and controlling the flow of information through the nervous system. By inhibiting the activity of certain neurons, IPSPs can help to sharpen the signals that are transmitted between neurons and prevent unwanted noise or interference from disrupting communication within the circuit.
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.
Acupuncture analgesia is a form of pain relief that involves the stimulation of specific points on the body, called acupoints, using thin needles. This technique is based on traditional Chinese medicine (TCM) principles, which suggest that energy, or "qi," flows through the body along pathways called meridians. According to TCM, blockages or imbalances in this flow of qi can lead to illness or pain. By inserting needles at specific acupoints, acupuncture is thought to help restore the balance and flow of qi, thereby alleviating pain and promoting healing.
In modern medical terms, acupuncture analgesia is believed to work by stimulating the nervous system and triggering the release of natural painkillers called endorphins. The needles may also cause localized changes in blood flow and inflammation, which can help reduce pain and promote healing in the affected area.
Acupuncture has been shown to be effective for a variety of pain conditions, including osteoarthritis, migraines, and chronic low back pain. However, it is important to note that acupuncture should be performed by a qualified practitioner and may not be suitable for everyone. As with any medical treatment, there are potential risks and side effects associated with acupuncture, including infection, bruising, and bleeding. It is always best to consult with a healthcare provider before starting any new treatment.
Unmyelinated nerve fibers, also known as unmyelinated axons or non-myelinated fibers, are nerve cells that lack a myelin sheath. Myelin is a fatty, insulating substance that surrounds the axon of many nerve cells and helps to increase the speed of electrical impulses traveling along the nerve fiber.
In unmyelinated nerve fibers, the axons are surrounded by a thin layer of Schwann cell processes called the endoneurium, but there is no continuous myelin sheath. Instead, the axons are packed closely together in bundles, with several axons lying within the same Schwann cell.
Unmyelinated nerve fibers tend to be smaller in diameter than myelinated fibers and conduct electrical impulses more slowly. They are commonly found in the autonomic nervous system, which controls involuntary functions such as heart rate, blood pressure, and digestion, as well as in sensory nerves that transmit pain and temperature signals.
Dihydroxytryptamines are a type of tryptamine that contains two hydroxyl groups (-OH) attached to its structure. Tryptamines are biogenic amines that are derived from the essential amino acid, tryptophan. They have various physiological and psychological effects in the human body. Dihydroxytryptamines, specifically, include several endogenous substances such as serotonin (5-hydroxytryptamine or 5-HT) and melatonin, which are important neurotransmitters and hormones involved in mood regulation, sleep-wake cycle, and other functions. Exogenous dihydroxytryptamines can also be found in some plants and animals and have been investigated for their potential psychoactive properties.
Stilbamidines are a class of chemical compounds that are primarily used as veterinary medicines, specifically as parasiticides for the treatment and prevention of ectoparasites such as ticks and lice in livestock animals. Stilbamidines belong to the family of chemicals known as formamidines, which are known to have insecticidal and acaricidal properties.
The most common stilbamidine compound is chlorphentermine, which has been used as an appetite suppressant in human medicine. However, its use as a weight loss drug was discontinued due to its addictive properties and potential for serious side effects.
It's important to note that Stilbamidines are not approved for use in humans and should only be used under the supervision of a veterinarian for the intended purpose of treating and preventing ectoparasites in animals.
Bicuculline is a pharmacological agent that acts as a competitive antagonist at GABA-A receptors, which are inhibitory neurotransmitter receptors in the central nervous system. By blocking the action of GABA (gamma-aminobutyric acid) at these receptors, bicuculline can increase neuronal excitability and cause convulsions. It is used in research to study the role of GABAergic neurotransmission in various physiological processes and neurological disorders.
The reticular formation is not a single structure but rather a complex network of interconnected neurons located in the brainstem, extending from the medulla oblongata through the pons and mesencephalon (midbrain) up to the diencephalon (thalamus and hypothalamus). It forms part of the reticular activating system, which is involved in regulating arousal, awareness, and sleep-wake cycles.
The reticular formation plays a crucial role in various functions such as:
1. Modulation of sensory input: The neurons in the reticular formation receive inputs from all senses (visual, auditory, tactile, etc.) and help filter and prioritize this information before it reaches higher cognitive areas.
2. Control of motor function: The reticular formation contributes to the regulation of muscle tone, posture, and locomotion by modulating the activity of motor neurons in the spinal cord.
3. Regulation of autonomic functions: The reticular formation is involved in controlling heart rate, blood pressure, respiration, and other visceral functions through its connections with the autonomic nervous system.
4. Consciousness and arousal: The ascending reticular activating system (ARAS) originates from the reticular formation and projects to the thalamus and cerebral cortex, where it helps maintain wakefulness and arousal. Damage to the ARAS can lead to coma or other states of altered consciousness.
5. Sleep-wake cycle regulation: The reticular formation contains cells that release neurotransmitters like histamine, serotonin, and orexin/hypocretin, which are essential for sleep-wake regulation. Dysfunction in these circuits has been implicated in various sleep disorders, such as narcolepsy and insomnia.
GABA (gamma-aminobutyric acid) agonists are substances that bind to and activate GABA receptors in the brain, mimicking the actions of GABA, which is the primary inhibitory neurotransmitter in the central nervous system. These agents can produce various effects such as sedation, anxiolysis, muscle relaxation, and anticonvulsant activity by enhancing the inhibitory tone in the brain. They are used clinically to treat conditions such as anxiety disorders, seizures, and muscle spasticity. Examples of GABA agonists include benzodiazepines, barbiturates, and certain non-benzodiazepine hypnotics.
GABA-A receptor antagonists are pharmacological agents that block the action of gamma-aminobutyric acid (GABA) at GABA-A receptors. GABA is the primary inhibitory neurotransmitter in the central nervous system, and it exerts its effects by binding to GABA-A receptors, which are ligand-gated chloride channels. When GABA binds to these receptors, it opens the chloride channel, leading to an influx of chloride ions into the neuron and hyperpolarization of the membrane, making it less likely to fire.
GABA-A receptor antagonists work by binding to the GABA-A receptor and preventing GABA from binding, thereby blocking the inhibitory effects of GABA. This can lead to increased neuronal excitability and can result in a variety of effects depending on the specific antagonist and the location of the receptors involved.
GABA-A receptor antagonists have been used in research to study the role of GABA in various physiological processes, and some have been investigated as potential therapeutic agents for conditions such as anxiety, depression, and insomnia. However, their use is limited by their potential to cause seizures and other adverse effects due to excessive neuronal excitation. Examples of GABA-A receptor antagonists include picrotoxin, bicuculline, and flumazenil.
Brain mapping is a broad term that refers to the techniques used to understand the structure and function of the brain. It involves creating maps of the various cognitive, emotional, and behavioral processes in the brain by correlating these processes with physical locations or activities within the nervous system. Brain mapping can be accomplished through a variety of methods, including functional magnetic resonance imaging (fMRI), positron emission tomography (PET) scans, electroencephalography (EEG), and others. These techniques allow researchers to observe which areas of the brain are active during different tasks or thoughts, helping to shed light on how the brain processes information and contributes to our experiences and behaviors. Brain mapping is an important area of research in neuroscience, with potential applications in the diagnosis and treatment of neurological and psychiatric disorders.
Cannabinoid receptor modulators are a class of compounds that interact with and modify the function of cannabinoid receptors, which are part of the endocannabinoid system in the human body. These receptors play a role in regulating various physiological processes such as pain, mood, memory, appetite, and immunity.
There are two main types of cannabinoid receptors: CB1 receptors, which are primarily found in the brain and central nervous system, and CB2 receptors, which are mainly found in the immune system and peripheral tissues. Cannabinoid receptor modulators can be classified into three categories based on their effects on these receptors:
1. Agonists: These compounds bind to and activate cannabinoid receptors, leading to a range of effects such as pain relief, anti-inflammation, and mood enhancement. Examples include THC (tetrahydrocannabinol), the psychoactive component of marijuana, and synthetic cannabinoids like dronabinol (Marinol) and nabilone (Cesamet).
2. Antagonists: These compounds bind to cannabinoid receptors but do not activate them, instead blocking or reducing the effects of agonist compounds. Examples include rimonabant (Acomplia), which was withdrawn from the market due to psychiatric side effects, and SR141716A.
3. Inverse Agonists: These compounds bind to cannabinoid receptors and produce effects opposite to those of agonist compounds. Examples include CBD (cannabidiol), a non-psychoactive component of marijuana that has anti-inflammatory, anxiolytic, and neuroprotective properties.
Cannabinoid receptor modulators have potential therapeutic applications in various medical conditions such as chronic pain, multiple sclerosis, epilepsy, cancer, and mental health disorders. However, further research is needed to fully understand their mechanisms of action and potential side effects.
The spinal cord is a major part of the nervous system, extending from the brainstem and continuing down to the lower back. It is a slender, tubular bundle of nerve fibers (axons) and support cells (glial cells) that carries signals between the brain and the rest of the body. The spinal cord primarily serves as a conduit for motor information, which travels from the brain to the muscles, and sensory information, which travels from the body to the brain. It also contains neurons that can independently process and respond to information within the spinal cord without direct input from the brain.
The spinal cord is protected by the bony vertebral column (spine) and is divided into 31 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Each segment corresponds to a specific region of the body and gives rise to pairs of spinal nerves that exit through the intervertebral foramina at each level.
The spinal cord is responsible for several vital functions, including:
1. Reflexes: Simple reflex actions, such as the withdrawal reflex when touching a hot surface, are mediated by the spinal cord without involving the brain.
2. Muscle control: The spinal cord carries motor signals from the brain to the muscles, enabling voluntary movement and muscle tone regulation.
3. Sensory perception: The spinal cord transmits sensory information, such as touch, temperature, pain, and vibration, from the body to the brain for processing and awareness.
4. Autonomic functions: The sympathetic and parasympathetic divisions of the autonomic nervous system originate in the thoracolumbar and sacral regions of the spinal cord, respectively, controlling involuntary physiological responses like heart rate, blood pressure, digestion, and respiration.
Damage to the spinal cord can result in various degrees of paralysis or loss of sensation below the level of injury, depending on the severity and location of the damage.
A cannabinoid receptor, CB1, is a G protein-coupled receptor that is primarily found in the brain and central nervous system. It is one of the two main types of cannabinoid receptors, the other being CB2, and is activated by the endocannabinoid anandamide and the phytocannabinoid Delta-9-tetrahydrocannabinol (THC), which is the primary psychoactive component of cannabis. The activation of CB1 receptors is responsible for many of the psychological effects of cannabis, including euphoria, altered sensory perception, and memory impairment. CB1 receptors are also found in peripheral tissues, such as the adipose tissue, liver, and muscles, where they play a role in regulating energy metabolism, appetite, and pain perception.
The lateral hypothalamic area (LHA) is a region in the hypothalamus, which is a part of the brain that plays a crucial role in regulating various autonomic functions and maintaining homeostasis. The LHA is located laterally to the third ventricle and contains several neuronal populations that are involved in diverse physiological processes such as feeding behavior, energy balance, sleep-wake regulation, and neuroendocrine function.
Some of the key neurons found in the LHA include orexin/hypocretin neurons, melanin-concentrating hormone (MCH) neurons, and agouti-related protein (AGRP) neurons. These neurons release neurotransmitters and neuropeptides that modulate various physiological functions, including appetite regulation, energy expenditure, and arousal. Dysfunction in the LHA has been implicated in several neurological and psychiatric disorders, such as narcolepsy, obesity, and depression.
The preoptic area (POA) is a region within the anterior hypothalamus of the brain. It is named for its location near the optic chiasm, where the optic nerves cross. The preoptic area is involved in various functions, including body temperature regulation, sexual behavior, and sleep-wake regulation.
The preoptic area contains several groups of neurons that are sensitive to changes in temperature and are responsible for generating heat through shivering or non-shivering thermogenesis. It also contains neurons that release inhibitory neurotransmitters such as GABA and galanin, which help regulate arousal and sleep.
Additionally, the preoptic area has been implicated in the regulation of sexual behavior, particularly in males. Certain populations of neurons within the preoptic area are involved in the expression of male sexual behavior, such as mounting and intromission.
Overall, the preoptic area is a critical region for the regulation of various physiological and behavioral functions, making it an important area of study in neuroscience research.
The mediodorsal thalamic nucleus (MDTN) is a collection of neurons located in the dorsal part of the thalamus, a region of the brain that serves as a relay station for sensory and motor signals to the cerebral cortex. The MDTN is primarily involved in cognitive functions such as memory, attention, and emotion regulation.
The MDTN receives inputs from various regions of the brain, including the prefrontal cortex, amygdala, and hippocampus, and projects to the same areas of the cerebral cortex. It has been implicated in several neurological and psychiatric conditions, such as Alzheimer's disease, Parkinson's disease, schizophrenia, and depression.
Anatomically, the MDTN is divided into several subnuclei, including the parvocellular, magnocellular, and intermediate parts, each with distinct connectivity patterns and functions. Overall, the MDTN plays a crucial role in integrating information from different brain regions to facilitate higher-order cognitive processes.
Endocannabinoids are naturally occurring compounds in the body that bind to cannabinoid receptors, which are found in various tissues and organs throughout the body. These compounds play a role in regulating many physiological processes, including appetite, mood, pain sensation, and memory. They are similar in structure to the active components of cannabis (marijuana), called phytocannabinoids, such as THC (tetrahydrocannabinol) and CBD (cannabidiol). However, endocannabinoids are produced by the body itself, whereas phytocannabinoids come from the cannabis plant. The two most well-known endocannabinoids are anandamide and 2-arachidonoylglycerol (2-AG).
Medical Definition:
Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.
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 hypothalamus is a small, vital region of the brain that lies just below the thalamus and forms part of the limbic system. It plays a crucial role in many important functions including:
1. Regulation of body temperature, hunger, thirst, fatigue, sleep, and circadian rhythms.
2. Production and regulation of hormones through its connection with the pituitary gland (the hypophysis). It controls the release of various hormones by producing releasing and inhibiting factors that regulate the anterior pituitary's function.
3. Emotional responses, behavior, and memory formation through its connections with the limbic system structures like the amygdala and hippocampus.
4. Autonomic nervous system regulation, which controls involuntary physiological functions such as heart rate, blood pressure, and digestion.
5. Regulation of the immune system by interacting with the autonomic nervous system.
Damage to the hypothalamus can lead to various disorders like diabetes insipidus, growth hormone deficiency, altered temperature regulation, sleep disturbances, and emotional or behavioral changes.
The habenula is a small, paired nucleus located in the epithalamus region of the brain. It plays a crucial role in the modulation of various functions such as mood, reward, and motivation. The habenula can be further divided into two subregions: the medial and lateral habenula.
The medial habenula is involved in the regulation of emotional behaviors, including responses to stress and anxiety. It receives inputs from several brain regions associated with emotion, such as the amygdala and hippocampus, and projects to the interpeduncular nucleus (IPN) in the midbrain.
The lateral habenula is primarily involved in processing aversive stimuli and modulating dopaminergic reward pathways. It receives inputs from various regions associated with motivation, learning, and memory, such as the prefrontal cortex, basal ganglia, and thalamus. The lateral habenula then projects to the midbrain's dopamine-producing neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc), which are critical components of the brain's reward system.
Dysfunction of the habenula has been implicated in several neurological and psychiatric disorders, including depression, anxiety, addiction, and schizophrenia.
Morphine dependence is a medical condition characterized by a physical and psychological dependency on morphine, a potent opioid analgesic. This dependence develops as a result of repeated use or abuse of morphine, leading to changes in the brain's reward and pleasure pathways. The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) outlines the following criteria for diagnosing opioid dependence, which includes morphine:
A. A problematic pattern of opioid use leading to clinically significant impairment or distress, as manifested by at least two of the following, occurring within a 12-month period:
1. Opioids are often taken in larger amounts or over a longer period than was intended.
2. There is a persistent desire or unsuccessful efforts to cut down or control opioid use.
3. A great deal of time is spent in activities necessary to obtain the opioid, use the opioid, or recover from its effects.
4. Craving, or a strong desire or urge to use opioids.
5. Recurrent opioid use resulting in a failure to fulfill major role obligations at work, school, or home.
6. Continued opioid use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of opioids.
7. Important social, occupational, or recreational activities are given up or reduced because of opioid use.
8. Recurrent opioid use in situations in which it is physically hazardous.
9. Continued opioid use despite knowing that a physical or psychological problem is likely to have been caused or exacerbated by opioids.
10. Tolerance, as defined by either of the following:
a. A need for markedly increased amounts of opioids to achieve intoxication or desired effect.
b. A markedly diminished effect with continued use of the same amount of an opioid.
11. Withdrawal, as manifested by either of the following:
a. The characteristic opioid withdrawal syndrome.
b. The same (or a closely related) substance is taken to relieve or avoid withdrawal symptoms.
Additionally, it's important to note that if someone has been using opioids for an extended period and suddenly stops taking them, they may experience withdrawal symptoms. These can include:
- Anxiety
- Muscle aches
- Insomnia
- Runny nose
- Sweating
- Diarrhea
- Nausea or vomiting
- Abdominal cramping
- Dilated pupils
If you or someone you know is struggling with opioid use, it's essential to seek professional help. There are many resources available, including inpatient and outpatient treatment programs, support groups, and medications that can help manage withdrawal symptoms and cravings.
Physical stimulation, in a medical context, refers to the application of external forces or agents to the body or its tissues to elicit a response. This can include various forms of touch, pressure, temperature, vibration, or electrical currents. The purpose of physical stimulation may be therapeutic, as in the case of massage or physical therapy, or diagnostic, as in the use of reflex tests. It is also used in research settings to study physiological responses and mechanisms.
In a broader sense, physical stimulation can also refer to the body's exposure to physical activity or exercise, which can have numerous health benefits, including improving cardiovascular function, increasing muscle strength and flexibility, and reducing the risk of chronic diseases.
Muscimol is defined as a cyclic psychoactive ingredient found in certain mushrooms, including Amanita muscaria and Amanita pantherina. It acts as a potent agonist at GABA-A receptors, which are involved in inhibitory neurotransmission in the central nervous system. Muscimol can cause symptoms such as altered consciousness, delirium, hallucinations, and seizures. It is used in research but has no medical applications.
Semicarbazides are organic compounds that contain the functional group -NH-CO-NH-NH2. They are derivatives of hydrazine and carbamic acid, with the general structure (CH3)NHCSNH2. Semicarbazides are widely used in the synthesis of various chemical compounds, including heterocyclic compounds, pharmaceuticals, and agrochemicals.
In a medical context, semicarbazides themselves do not have any therapeutic use. However, they can be used in the preparation of certain drugs or drug intermediates. For example, semicarbazones, which are derivatives of semicarbazides, can be used to synthesize some antituberculosis drugs.
It is worth noting that semicarbazides and their derivatives have been found to have mutagenic and carcinogenic properties in some studies. Therefore, they should be handled with care in laboratory settings, and exposure should be minimized to reduce potential health risks.
"Cat" is a common name that refers to various species of small carnivorous mammals that belong to the family Felidae. The domestic cat, also known as Felis catus or Felis silvestris catus, is a popular pet and companion animal. It is a subspecies of the wildcat, which is found in Europe, Africa, and Asia.
Domestic cats are often kept as pets because of their companionship, playful behavior, and ability to hunt vermin. They are also valued for their ability to provide emotional support and therapy to people. Cats are obligate carnivores, which means that they require a diet that consists mainly of meat to meet their nutritional needs.
Cats are known for their agility, sharp senses, and predatory instincts. They have retractable claws, which they use for hunting and self-defense. Cats also have a keen sense of smell, hearing, and vision, which allow them to detect prey and navigate their environment.
In medical terms, cats can be hosts to various parasites and diseases that can affect humans and other animals. Some common feline diseases include rabies, feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and toxoplasmosis. It is important for cat owners to keep their pets healthy and up-to-date on vaccinations and preventative treatments to protect both the cats and their human companions.
GABA (gamma-aminobutyric acid) antagonists are substances that block the action of GABA, which is the primary inhibitory neurotransmitter in the central nervous system. GABA plays a crucial role in regulating neuronal excitability and reducing the transmission of nerve impulses.
GABA antagonists work by binding to the GABA receptors without activating them, thereby preventing the normal function of GABA and increasing neuronal activity. These agents can cause excitation of the nervous system, leading to various effects depending on the specific type of GABA receptor they target.
GABA antagonists are used in medical treatments for certain conditions, such as sleep disorders, depression, and cognitive enhancement. However, they can also have adverse effects, including anxiety, agitation, seizures, and even neurotoxicity at high doses. Examples of GABA antagonists include picrotoxin, bicuculline, and flumazenil.
Opioid delta receptors, also known as delta opioid receptors (DORs), are a type of G protein-coupled receptor found in the nervous system and other tissues throughout the body. They belong to the opioid receptor family, which includes mu, delta, and kappa receptors. These receptors play an essential role in pain modulation, reward processing, and addictive behaviors.
Delta opioid receptors are activated by endogenous opioid peptides such as enkephalins and exogenous opioids like synthetic drugs. Once activated, they trigger a series of intracellular signaling events that can lead to inhibition of neuronal excitability, reduced neurotransmitter release, and ultimately, pain relief.
Delta opioid receptors have also been implicated in various physiological processes, including immune function, respiratory regulation, and gastrointestinal motility. However, their clinical use as therapeutic targets has been limited due to the development of tolerance and potential adverse effects such as sedation and respiratory depression.
In summary, delta opioid receptors are a type of opioid receptor that plays an essential role in pain modulation and other physiological processes. They are activated by endogenous and exogenous opioids and trigger intracellular signaling events leading to various effects, including pain relief. However, their clinical use as therapeutic targets is limited due to potential adverse effects.
Animal vocalization refers to the production of sound by animals through the use of the vocal organs, such as the larynx in mammals or the syrinx in birds. These sounds can serve various purposes, including communication, expressing emotions, attracting mates, warning others of danger, and establishing territory. The complexity and diversity of animal vocalizations are vast, with some species capable of producing intricate songs or using specific calls to convey different messages. In a broader sense, animal vocalizations can also include sounds produced through other means, such as stridulation in insects.
Maternal behavior refers to the nurturing and protective behaviors exhibited by a female animal towards its offspring. In humans, this term is often used to describe the natural instincts and actions of a woman during pregnancy, childbirth, and early child-rearing. It encompasses a broad range of activities such as feeding, grooming, protecting, and teaching the young.
In the context of medical and psychological research, maternal behavior is often studied to understand the factors that influence its development, expression, and outcomes for both the mother and offspring. Factors that can affect maternal behavior include hormonal changes during pregnancy and childbirth, as well as social, cultural, and environmental influences.
Abnormal or atypical maternal behavior may indicate underlying mental health issues, such as postpartum depression or anxiety, and can have negative consequences for both the mother and the child's development and well-being. Therefore, it is important to monitor and support healthy maternal behaviors in new mothers to promote positive outcomes for both parties.
Periaqueductal gray
Wernicke encephalopathy
Sham rage
Hypothalamus
Deep brain stimulation
Hypothalamospinal tract
AP-7 (drug)
RGS17
Hyperalgesia
Urination
Pretectal area
Medial longitudinal fasciculus
PD-102,807
Mammal
Lordosis behavior
Midbrain tegmentum
Rostral ventromedial medulla
Menthol
Volvation
Nucleus raphe magnus
Cannabinoid receptor 1
Zona incerta
Mesencephalic nucleus of trigeminal nerve
Klazomania
Human penis
Cardiac fibrosis
Arrestin beta 2
Bay R 1531
Urinary system
Escape response
Periaqueductal gray - Wikipedia
Opioid presynaptic disinhibition of the midbrain periaqueductal grey descending analgesic pathway
Local Opioid Withdrawal in Rat Single Periaqueductal Gray NeuronsIn Vitro | Journal of Neuroscience
Differential Encoding of Predator Fear in the Ventromedial Hypothalamus and Periaqueductal Grey | Journal of Neuroscience
Frontiers | Linking Pain Sensation to the Autonomic Nervous System: The Role of the Anterior Cingulate and Periaqueductal Gray...
Differentiated roles of the periaqueductal gray and the paralemniscal area on vocalization in the new world bat Phyllostomus...
Periaqueductal Gray | CU Experts | CU Boulder
What Is the Periaqueductal Gray? (with pictures)
Divergent Modulation of Nociception by Glutamatergic and GABAergic Neuronal Subpopulations in the Periaqueductal Gray | eNeuro
Esr1+ cells in the ventromedial hypothalamus control female aggression | Nature Neuroscience
Bladder Dysfunction Associated With Multiple Sclerosis
Electroacupuncture Pretreatment at GB20 Exerts Antinociceptive Effects via Peripheral and Central Serotonin Mechanism in...
Sensory thalamus and periaqueductal grey area local field potential signals during bladder filling. - Nuffield Department of...
Figure 3 - Isolation of Prion with BSE Properties from Farmed Goat - Volume 17, Number 12-December 2011 - Emerging Infectious...
GPR30 receptor promotes preoperative anxiety-induced postoperative hyperalgesia by up-regulating GABAA-α4β1δ subunits in...
Voxel-based morphometry--the methods
Mathieu Roy | Department of Psychology - McGill University
Association of Peri-ictal Brainstem Posturing With Seizure Severity and Breathing Compromise in Patients With Generalized...
Netter's Atlas of Neuroscience Elsevier eBook on VitalSource (Retail Access Card), 4th Edition - 9780323756587
BRAINMAPS.ORG - BRAIN ATLAS, BRAIN MAPS, BRAIN STRUCTURE, NEUROINFORMATICS, BRAIN, STEREOTAXIC ATLAS, NEUROSCIENCE
Epistaxis: Practice Essentials, Anatomy, Pathophysiology
Multiple System Atrophy: Practice Essentials, Background, Etiology and Pathophysiology
Manipulating the placebo effect | Interviews
Epistaxis Treatment & Management: Approach Considerations, Manual Hemostasis, Humidification and Moisturization
Tissue expression of NLRP2 - Staining in midbrain - The Human Protein Atlas
Medscape | Soc Cogn Affect Neurosci - Content Listing
Neural roots/origins of alcoholism identified | ScienceDaily
Shining a light on pain | Nature Reviews Neuroscience
Irene Tracey's research works | University of Oxford, Oxford (OX) and other places
Ventrolateral periaqueductal gray3
- Opioid dependence in ventrolateral periaqueductal gray (PAG) neurons was studied by using intracellular recordings from brain slices. (jneurosci.org)
- The four columns are the dorsomedial periaqueductal gray , dorsolateral periaqueductal gray , lateral periaqueductal gray , and ventrolateral periaqueductal gray . (washington.edu)
- This mechanism leverages the neurotransmitter acetylcholine in the ventrolateral periaqueductal gray (vlPAG) region of the brain. (neurosciencenews.com)
Neurons2
- Stimulation of the periaqueductal gray matter of the midbrain activates enkephalin-releasing neurons that project to the raphe nuclei in the brainstem. (wikipedia.org)
- Studies have shown that the GABA A receptor subunits α4, β1, and δ in the periaqueductal gray (PAG) neurons promote the descending facilitation system. (biomedcentral.com)
Analgesia1
- The periaqueductal grey is responsible for bonding, analgesia, and quiescence among other things. (databasefootball.com)
Midbrain periaqueductal1
- The midbrain periaqueductal grey (PAG) plays a central role in modulating pain through a descending pathway that projects indirectly to the spinal cord via the rostroventral medial medulla (RVM). (nih.gov)
Thalamus6
- Sensory thalamus and periaqueductal grey area local field potential signals during bladder filling. (ox.ac.uk)
- The periaqueductal grey area and sensory thalamus are thought to be important nuclei involved in the supraspinal bladder control network. (ox.ac.uk)
- In a single patient, we have recorded local field potential signals from implanted deep brain stimulation electrodes within the sensory thalamus during filling cystometry with periaqueductal grey area deep brain stimulation in the ON and OFF states. (ox.ac.uk)
- Stimulation of the periaqueductal grey area abolishes this correlated activity in the gamma frequency band and also suppresses oscillations within the sensory thalamus in the alpha frequency band. (ox.ac.uk)
- They also suggest that periaqueductal grey area deep brain stimulation may disrupt the normal processing of afferent signals within the sensory thalamus which may be related to the effect of stimulation on bladder capacity. (ox.ac.uk)
- Depth Brain Neurostimulation - The stereotactic implantation of electrodes in the deep brain (e.g., thalamus and periaqueductal gray matter) is covered. (cms.gov)
Pontine micturition center1
- Cognitive control of micturition is achieved by communication from a number of brain structures to the periaqueductal gray matter, which then exerts control over the pontine micturition center to suppress or trigger a voiding reflex. (medscape.com)
Ventromedial medulla1
- MRI section of human mid-brain showing periaqueductal gray Rostral ventromedial medulla Emotion Faull, Olivia K. (wikipedia.org)
Ventral2
- In the periaqueductal gray matter, mice challenged with the suspected case (B) and with BSE controls (D and F) showed a manifold lower staining intensity of PrP Sc labeling compared with the surrounding area, but the scrapie control (H) showed an intense labeling in the ventral periaqueductal region associated with substantial reduction of labeling in all neighboring areas. (cdc.gov)
- The periaqueductal gray is distinguished from the cellular structures ventral to the aqueduct by its homogeneity. (washington.edu)
Stimulation3
- The major efferent target of the ventromedial hypothalamus is the dorsal periaqueductal gray (dPAG), and stimulation of this structure also elicits flight, freezing, and sympathetic activation. (jneurosci.org)
- As indicators of autonomic function, we examined how heart rate variability (HRV) frequency measures were influenced by tonic noxious stimulation and how these variables related to participants' pain perception and to brain functional connectivity in regions known to play a role in both ANS regulation and pain perception, namely the right dorsal anterior cingulate cortex (dACC) and periaqueductal gray (PAG). (frontiersin.org)
- Deep brain stimulation of the periqueductal grey area has been shown to increase bladder capacity in the human. (ox.ac.uk)
DPAG1
- The medial orbitofrontal cortex (mOFC) at the front of the brain senses an unpleasant or emergency situation, and then sends this information to the dorsal periaqueductal gray (dPAG) at the brain's core, the latter area processing whether we need to escape the situation. (sciencedaily.com)
Raphe2
- Are periaqueductal grey and dorsal raphe the foundation of appetitive and aversive control? (wikipedia.org)
- In the central nervous system (CNS), the serotonergic system from the brainstem rostroventromedial medulla (RVM) region, including the nucleus raphe magnus (NRM) and nucleus reticularis paragigantocellularis (NpGC) nuclei, has descending projections to the trigeminal nucleus caudalis (TNC) and widespread projections to the forebrain through the periaqueductal gray (PAG) [ 18 ]. (hindawi.com)
Elicits1
- When fear is near: Threat imminence elicits prefrontal-periaqueductal gray shifts in humans. (mpg.de)
Roles3
- However, reversible inhibition experiments suggest that the ventromedial hypothalamus and periaqueductal gray play distinct roles in the control of defensive behavior, with the former proposed to encode an internal state necessary for the motivation of defensive responses, while the latter serves as a motor pattern initiator. (jneurosci.org)
- The periaqueductal gray, or PAG, is an area of the mammal brain that plays several important roles in mediating pain perception, reproductive behavior, and cardiovascular activity. (thehealthboard.com)
- The roles of the periaqueductal gray may extend beyond those listed, as well. (thehealthboard.com)
Glutamatergic1
- Glutamatergic mechanisms of the dorsal periaqueductal gray matter modulate the expression of conditioned freezing and fear-potentiated startle. (harvard.edu)
Matter8
- The periaqueductal gray is the gray matter located around the cerebral aqueduct within the tegmentum of the midbrain. (wikipedia.org)
- At its simplest, voxel-based morphometry (VBM) involves a voxel-wise comparison of the local concentration of gray matter between two groups of subjects. (nih.gov)
- This is followed by segmenting the gray matter from the spatially normalized images and smoothing the gray-matter segments. (nih.gov)
- Voxel-wise parametric statistical tests which compare the smoothed gray-matter images from the two groups are performed. (nih.gov)
- This paper describes the steps involved in VBM, with particular emphasis on segmenting gray matter from MR images with nonuniformity artifact. (nih.gov)
- Chris - This is the Periaqueductal gray matter isnt it? (thenakedscientists.com)
- The pons relays afferent information from the bladder to higher brain centers, which in turn communicate with the periaqueductal gray matter, a relay station that collects higher brain center intput and processes this in order to signal the PMC to trigger or suppress the voiding reflex. (medscape.com)
- Usually the brain takes over the control of the pons, via the periaqueducatal gray matter, when children undergo toilet training. (medscape.com)
Tegmentum1
- Right cerebral aqueduct is surrounded by the periaqueductal gray and is found in between the tegmentum and the tectum. (databasefootball.com)
Cerebral1
- The term periaqueductal gray refers to the densely cellular core-structure surrounding the dorsal and lateral aspects of the cerebral aqueduct of the midbrain . (washington.edu)
Area2
- Studies have shown that the periaqueductal gray area of the brain may control cardiovascular activity. (thehealthboard.com)
- A visual circuit related to the periaqueductal gray area for the antinociceptive effects of bright light treatment. (nature.com)
Involvement2
- Another important duty of the periaqueductal gray seems to be an involvement in reproductive activity. (thehealthboard.com)
- Involvement of the benzodiazepine binding sites in the dorsal periaqueductal gray. (usp.br)
Behavior1
- The periaqueductal gray (PAG, also known as the central gray) is a brain region that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. (wikipedia.org)
Aversive1
- Representation of aversive prediction error in the human periaqueductal gray. (mcgill.ca)
Pain2
- The periaqueductal gray is also activated by viewing distressing images associated with pain. (wikipedia.org)
- Primarily, the periaqueductal gray function that has been well-studied is the way it influences the perception of pain. (thehealthboard.com)
Threat1
- Correction to: A 7-Tesla MRI study of the periaqueductal gray: resting state and task activation under threat. (medscape.com)
Shown1
- Studies at the University of Naples in Italy have shown that the periaqueductal gray can affect cardiovascular activity. (thehealthboard.com)
Study1
- A new study in mice shows that bright light reduces nocifensive behaviours via a visual circuit involving the periaqueductal grey (PAG). (nature.com)