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Hypoalgesia
Hypoalgesia or hypalgesia denotes a decreased sensitivity to painful stimuli. Hypoalgesia occurs when nociceptive (painful) stimuli are interrupted or decreased somewhere along the path between the input (nociceptors), and the places where they are processed and recognized as pain in the conscious mind. Hypoalgesic effects can be mild, such as massaging a stubbed toe to make it hurt less or taking aspirin to decrease a headache, or they can be severe, like being under strong anesthesia. Hypoalgesia can be caused by exogenous chemicals such as opioids, as well as by chemicals produced by the body in phenomena such as fear- and exercise- induced hypoalgesia. Hypoalgesia can also be associated with diseases, such as CIPA or in less severe cases with diabetes or other diseases associated with hypertension. Chemical causes Analgesics Analgesics are a class of biochemicals that cause hypoalgesia. Analgesics can act on both the peripheral and central nervous systems to decrease pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperalgesia
Hyperalgesia ( or ; ''hyper'' from Greek ὑπέρ (''huper'') 'over' + ''-algesia'' from Greek ἄλγος (algos) 'pain') is an abnormally increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves and can cause hypersensitivity to stimulus. Prostaglandins E and F are largely responsible for sensitizing the nociceptors. Temporary increased sensitivity to pain also occurs as part of sickness behavior, the evolved response to infection. Types Hyperalgesia can be experienced in focal, discrete areas, or as a more diffuse, body-wide form. Conditioning studies have established that it is possible to experience a learned hyperalgesia of the latter, diffuse form. The focal form is typically associated with injury, and is divided into two subtypes: * ''Primary hyperalgesia'' describes pain sensitivity that occurs directly in the damaged tissues. * ''Secondary hyperalgesia'' describes pain sensitivity that occurs in surrounding undamaged ti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nociceptive
In physiology, nociception , also nocioception; ) is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular signal, and recognize and characterize the signal to trigger an appropriate defensive response. In nociception, intense chemical (e.g., capsaicin present in chili pepper or cayenne pepper), mechanical (e.g., cutting, crushing), or thermal (heat and cold) stimulation of sensory neurons called nociceptors produces a signal that travels along a chain of nerve fibers to the brain. Nociception triggers a variety of physiological and behavioral responses to protect the organism against an aggression, and usually results in a subjective experience, or perception, of pain in sentient beings. Detection of noxious stimuli Potentially damaging mechanical, thermal, and chemical stimuli are detected by nerve endings called nociceptors, which are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opium
Opium (also known as poppy tears, or Lachryma papaveris) is the dried latex obtained from the seed Capsule (fruit), capsules of the opium poppy ''Papaver somniferum''. Approximately 12 percent of opium is made up of the analgesic alkaloid morphine, which is processed chemically to produce heroin and other synthetic opioids for medicinal use and for the illegal drug trade. Opium's main psychoactive alkaloids, primarily morphine, act on μ-opioid receptors, causing analgesia and addiction with long-term use leading to tolerance, dependence, and increased cancer risk. The latex also contains the closely related opiates codeine and thebaine, and non-analgesic alkaloids such as papaverine and noscapine. The traditional, labor-intensive method of obtaining the latex is to scratch ("score") the immature seed pods (fruits) by hand; the latex leaks out and dries to a sticky yellowish residue that is later scraped off and dehydrated. The English word for opium is loan word, borrowed fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diabetic Neuropathy
Diabetic neuropathy includes various types of nerve damage associated with diabetes mellitus. The most common form, diabetic peripheral neuropathy, affects 30% of all diabetic patients. Studies suggests that cutaneous nerve branches, such as the sural nerve, are involved in more than half of patients with diabetes 10 years after the diagnosis and can be detected with high-resolution magnetic resonance imaging. Symptoms depend on the site of nerve damage and can include motor changes such as weakness; sensory symptoms such as numbness, tingling, or pain; or autonomic changes such as urinary symptoms. These changes are thought to result from a microvascular disease, microvascular injury involving small blood vessels that supply nerves (vasa nervorum). Relatively common conditions which may be associated with diabetic neuropathy include distal symmetric polyneuropathy; Oculomotor nerve palsy, third, Fourth nerve palsy, fourth, or Sixth nerve palsy, sixth cranial nerve palsy; mononeuro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hereditary Sensory And Autonomic Neuropathy
Hereditary sensory and autonomic neuropathy (HSAN) or hereditary sensory neuropathy (HSN) is a condition used to describe any of the types of this disease which inhibit sensation. They are less common than Charcot-Marie-Tooth disease. Classification Eight different clinical entities have been described under hereditary sensory and autonomic neuropathies – all characterized by progressive loss of function that predominantly affects the peripheral sensory nerves. Their incidence has been estimated to be about 1 in 250,000. Type 1 Hereditary sensory neuropathy type 1 is a condition characterized by nerve abnormalities in the legs and feet (peripheral neuropathy). Many people with this condition have tingling, weakness, and a reduced ability to feel pain and sense hot and cold. Some affected individuals do not lose sensation, but instead feel shooting pains in their legs and feet. As the disorder progresses, the sensory abnormalities can affect the hands, arms, shoulders, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endomorphins
Endomorphins are natural, endogenous opioid neuropeptides that are considered to be central to pain relief. They were first described in 1997 by James Zadina, Abba Kastin and colleagues. The two known endomorphins, endomorphin-1 and endomorphin-2, are tetrapeptides, consisting of Tyr-Pro-Trp-Phe and Tyr-Pro-Phe-Phe amino acid sequences respectively. These sequences fold into tertiary structures with high specificity and affinity for the μ-opioid receptor, binding it exclusively and strongly. Bound μ-opioid receptors typically induce inhibitory effects on neuronal activity. Endomorphin-like immunoreactivity exists within the central and peripheral nervous systems, where endomorphin-1 appears to be concentrated in the brain and upper brainstem, and endomorphin-2 is located mainly in the spinal cord and lower brainstem. Because endomorphins activate the μ-opioid receptor, which is the target receptor of morphine and its derivatives, endomorphins possess significant potential as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynorphins
Dynorphins (Dyn) are a class of opioid peptides that arise from the precursor protein prodynorphin. When prodynorphin is cleaved during processing by proprotein convertase 2 (PC2), multiple active peptides are released: dynorphin A, dynorphin B, and α/ β-neoendorphin. Depolarization of a neuron containing prodynorphin stimulates PC2 processing, which occurs within synaptic vesicles in the presynaptic terminal. Occasionally, prodynorphin is not fully processed, leading to the release of "big dynorphin". "Big dynorphin" is a 32-amino acid molecule consisting of both dynorphin A and dynorphin B. Dynorphin A, dynorphin B, and big dynorphin all contain a high proportion of basic amino acid residues, in particular lysine and arginine (29.4%, 23.1%, and 31.2% basic residues, respectively), as well as many hydrophobic residues (41.2%, 30.8%, and 34.4% hydrophobic residues, respectively). Although dynorphins are found widely distributed in the CNS, they have the highest concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enkephalins
An enkephalin is a pentapeptide involved in regulating nociception (pain sensation) in the body. The enkephalins are termed endogenous ligands, as they are internally derived (and therefore endogenous) and bind as ligands 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 is Tyr-Gly-Gly-Phe-Leu. Endogenous opioid peptides There are three well-characterized families of opioid peptides produced by the body: enkephalins, β-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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endorphins
Endorphins (contracted from endogenous morphine) are peptides produced in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in the pituitary gland of the brain. Endorphins are endogenous painkillers often produced in the brain and adrenal medulla during physical exercise or orgasm and inhibit pain, muscle cramps, and relieve stress. History Opioid peptides in the brain were first discovered in 1973 by investigators at the University of Aberdeen, John Hughes and Hans Kosterlitz. They isolated "enkephalins" (from the Greek ) from pig brain, identified as Met-enkephalin and Leu-enkephalin. This came after the discovery of a receptor that was proposed to produce the pain-relieving analgesic effects of morphine and other opioids, which led Kosterlitz and Hughes to their discovery of the endogenous opioid ligands. Research during this time was focused on the search for a painkiller that did not have the addictive charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opioid Receptor
Opioid receptors are a group of inhibitory G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin. The opioid receptors are ~40% identical to somatostatin receptors (SSTRs). Opioid receptors are distributed widely in the brain, in the spinal cord, on peripheral neurons, and digestive tract. Discovery By the mid-1960s, it had become apparent from pharmacologic studies that opioids were likely to exert their actions at specific receptor sites, and that there were likely to be multiple such sites. Early studies had indicated that opiates appeared to accumulate in the brain. The receptors were first identified as specific molecules through the use of binding studies, in which opiates that had been labeled with radioisotopes were found to bind to brain membrane homogenates. The first such study was published in 1971, using 3H- levorphanol. In 1973, Candace Pert and Solomon H. Snyder publi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Codeine
Codeine is an opiate and prodrug of morphine mainly used to treat pain, coughing, and diarrhea. It is also commonly used as a recreational drug. It is found naturally in the sap of the opium poppy, ''Papaver somniferum''. It is typically used to treat mild to moderate degrees of pain. Greater benefit may occur when combined with paracetamol (acetaminophen) or a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen. Evidence does not support its use for acute cough suppression in children. In Europe, it is not recommended as a cough medicine for those under 12 years of age. It is generally taken by mouth. It typically starts working after half an hour, with maximum effect at two hours. Its effects last for about four to six hours. Codeine exhibits abuse potential similar to other opioid medications, including a risk of addiction and overdose. Common side effects include nausea, vomiting, constipation, itchiness, lightheadedness, and drowsiness. Serious ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
