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Lateral Raphespinal Tract
The raphespinal tract is a descending spinal cord tract located in the medulla oblongata. It consists of two tracts an anterior raphespinal tract, and a lateral raphespinal tract that mainly descend in the lateral funiculus. Fibers descend in the ventral portion of the lateral funiculus, mainly bilaterally to terminate in laminae I, II, and IV. The tract emerges from three of the raphe nuclei, the magnus, obscurus, and pallidus. The fibers of the raphespinal tract are mainly serotonergic. When raphe nuclei are stimulated they release serotonin which modulates the transmission of pain. Pathways Pain pathways converging upon the raphe nuclei to modulate pain via the raphespinal tract include: ** Laminae I and V of spinal cord→ spinomesencephalic tract → periaqueductal gray → nucleus raphe magnus → ** Laminae I and V of spinal cord → spinomesencephalic tract → mesencephalon raphe nuclei → ** Nociceptive group C first-order nerve fiber → interneuron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Cord Tract
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spinal cord, which contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone, passing through the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae. The spinal cord extends down to between the first and second lumbar vertebrae, where it ends. The enclosing bony vertebral column protects the relatively shorter spinal cord. It is around long in adult men and around long in adult women. The diameter of the spinal cord ranges from in the cervical and lumbar regions to in the thoracic area. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interneuron
Interneurons (also called internuncial neurons, relay neurons, association neurons, connector neurons, intermediate neurons or local circuit neurons) are neurons that connect two brain regions, i.e. not direct motor neurons or sensory neurons. Interneurons are the central nodes of neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS). They play vital roles in reflexes, neuronal oscillations, and neurogenesis in the adult mammalian brain. Interneurons can be further broken down into two groups: local interneurons and relay interneurons. Local interneurons have short axons and form circuits with nearby neurons to analyze small pieces of information. Relay interneurons have long axons and connect circuits of neurons in one region of the brain with those in other regions. However, interneurons are generally considered to operate mainly within local brain areas. The interaction between interneurons allow the brain to perform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsolateral Pontine Reticular Formation
The dorsolateral pontine reticular formation contains noradrenergic pain-inhibiting neurons which project to inhibitory interneurons of the substantia gelatinosa of the posterior grey column in the spinal cord. It thus complements the classical serotonergic-opioid peptide descending pain-inhibiting system: whereas the serotonergic-opioid peptide pathway ultimately pre-synaptically inhibits first-order nociceptive group C neurons, the DLPRF inhibits - by way of presumably GABAergic inhibitory interneurons - the second-order neurons of the ascending pain pathway. The DLPRF pathway is not affected by opioid agonists or antagonists. It is also involved in REM sleep. See also * Raphespinal tract - the canonical descending pain-inhibiting pathway which the DLPRF functionally complements. * Reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spasticity
Spasticity () is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles. Clinically, spasticity results from the loss of inhibition of motor neurons, causing excessive velocity-dependent muscle contraction. This ultimately leads to hyperreflexia, an exaggerated deep tendon reflex. Spasticity is often treated with the drug baclofen, which acts as an agonist at GABA receptors, which are inhibitory. Spastic cerebral palsy is the most common form of cerebral palsy, which is a group of permanent movement problems that do not get worse over time. GABA's inhibitory actions contribute to baclofen's efficacy as an anti-spasticity agent. Cause Spasticity mostly occurs in disorders of the central nervous system (CNS) affecting the upper motor neurons in the form of a lesion, such as spastic diplegia, or upper mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opioid
Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use disorder, reversing opioid overdose, and suppressing cough. Extremely potent opioids such as carfentanil are approved only for veterinary use. Opioids are also frequently used non-medically for their euphoric effects or to prevent withdrawal. Opioids can cause death and have been used for executions in the United States. Side effects of opioids may include itchiness, sedation, nausea, respiratory depression, constipation, and euphoria. Long-term use can cause tolerance, meaning that increased doses are required to achieve the same effect, and physical dependence, meaning that abruptly discontinuing the drug leads to unpleasant withdrawal symptoms. The euphoria attracts recreational use, and frequent, escalating recreational ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opioid Antagonist
An opioid antagonist, or opioid receptor antagonist, is a receptor antagonist that acts on one or more of the opioid receptors. Naloxone and naltrexone are commonly used opioid antagonist drugs which are competitive antagonists that bind to the opioid receptors with higher affinity than agonists but do not activate the receptors. This effectively blocks the receptor, preventing the body from responding to opioids and endorphins. Some opioid antagonists are not pure antagonists but do produce some weak opioid partial agonist effects, and can produce analgesic effects when administered in high doses to opioid-naive individuals. Examples of such compounds include nalorphine and levallorphan. However, the analgesic effects from these specific drugs are limited and tend to be accompanied by dysphoria, most likely due to additional agonist action at the κ-opioid receptor. As they induce opioid withdrawal effects in people who are taking, or have recently used, opioid full agonist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analgesia
Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals provide some pain control in the normal course of their practice, and for the more complex instances of pain, they also call on additional help from a specific medical specialty devoted to pain, which is called pain medicine. Pain management often uses a multidisciplinary approach for easing the suffering and improving the quality of life of anyone experiencing pain, whether acute pain or chronic pain. Relief of pain in general (analgesia) is often an acute affair, whereas managing chronic pain requires additional dimensions. The typical pain management team includes medical practitioners, pharmacists, clinical psychologists, physiotherapists, occupational therapists, recreational therapists, physician assistants, nurses, and de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enkephalin
An enkephalin is a pentapeptide involved in regulating nociception in the body. The enkephalins are termed endogenous ligands, as they are internally derived and bind to the body's opioid receptors. Discovered in 1975, two forms of enkephalin have been found, one containing leucine ("leu"), and the other containing methionine ("met"). Both are products of the proenkephalin gene. * Met-enkephalin is Tyr-Gly-Gly-Phe-Met. * Leu-enkephalin has Tyr-Gly-Gly-Phe-Leu. Endogenous opioid peptides There are three well-characterized families of opioid peptides produced by the body: enkephalins, B-endorphin, and dynorphins. The met-enkephalin peptide sequence is coded for by the enkephalin gene; the leu-enkephalin peptide sequence is coded for by both the enkephalin gene and the dynorphin gene. The proopiomelanocortin gene ( POMC) also contains the met-enkephalin sequence on the N-terminus of beta-endorphin, but the endorphin peptide is not processed into enkephalin. Effects on stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serotonin
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vasoconstriction. Approximately 90% of the serotonin that the body produces is in the intestinal tract. Biochemically, the indoleamine molecule derives from the amino acid tryptophan, via the (rate-limiting) Tryptophan hydroxylase, hydroxylation of the 5 position on the ring (forming the intermediate 5-Hydroxytryptophan, 5-hydroxytryptophan), and then Aromatic L-amino acid decarboxylase, decarboxylation to produce serotonin. Serotonin is primarily found in the enteric nervous system located in the human gastrointestinal tract, gastrointestinal tract (GI tract). However, it is also produced in the central nervous system (CNS), specifically in the raphe nuclei located in the brainstem, Merkel cells located in the skin, Neuroendocrine cell#Pulmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Trigeminal Nucleus
The spinal trigeminal nucleus is a nucleus in the medulla that receives information about deep/crude touch, pain, and temperature from the ipsilateral face. In addition to the trigeminal nerve (CN V), the facial (CN VII), glossopharyngeal (CN IX), and vagus nerves (CN X) also convey pain information from their areas to the spinal trigeminal nucleus. Thus the spinal trigeminal nucleus receives input from V, VII, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantocellular Reticular Nucleus
The gigantocellular reticular nucleus (Gi) is a subregion of the medullary reticular formation. As the name indicates, it consists mainly of so-called giant neuronal cells. This nucleus has been known to innervate the caudal hypoglossal nucleus, and responds to glutamatergic stimuli. The gigantocellular nucleus excites the hypoglossal nucleus, and can play a role in the actions of the said nerve.Yang, CC et al. Excitatory innervation of caudal hypoglossal nucleus from nucleus reticularis gigantocellularis in the rat. Neuroscience. 1995 Mar;65(2):365-74. It additionally receives connections from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular reticular nucleus. Retrograde studies have shown that the deep mesencephalic reticular formation and oral pontine reticular nucleus project to the gigantocellular nucleus. The dorsal rostral section of the nucleus reticularis gigantocellularis is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinoreticular Tract
The spinoreticular tract is an ascending pathway in the white matter of the spinal cord, positioned closely to the lateral spinothalamic tract. The tract is from spinal cord—to reticular formation— to thalamus. It is responsible for automatic responses to pain, such as in the case of injury. Pathway The spinoreticular tract utilizes four levels of neurons, unlike most ascending tracts which have first- through third-order neurons. The tract begins with first-order neurons, which immediately synapse with second-order neurons in the anterior (laminae VII and VIII) and posterior grey horns (lamina V) of the spinal column.Gray's Anatomy, 41st edition, p. 301 These neurons decussate to the opposite side (anterolateral, although in the cervical region many axons remain ipsilateral), and travel up the spinal column. It terminates in the brainstem at the medullary-pontine reticular formation The reticular formation is a set of interconnected nuclei that are located throughou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
