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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biologically active peptides aree typified by their unbiquity of distribution, their high receptor affinity and an almost infinite diversity of structure. For these reasons, considerable effort is now being expended to elucidate the possible role of peptides in brain function. This effort has been stimulated by the discovery of a number of new endogenous peptides, such as the enkephalins, endorphins, vasoactive intestinal peptide and neurotensin. At present, there is no clearly defined role for these peptides, although they may form an important basis for the chemical coding of various brain functions, including pain, mood and memory. At present, the potential for drug development of peptide agonists remains in fairly circumscribed areas such as analgesia, pituitary hormone control, and gastrointestinal motor and secretory control. Peptide antagonists may provide a vast field for future development, although only one area, that of antifertility drugs based on LHRH antagonists, shows any promise of immediate success. Industrial research approaches to new peptide agonists and antagonists mainly rely at present on rational drug design through structural analogies. Other fruitful approaches to be considered are the screening of natural microbial and plant products and the possible application of genetic engineering techniques.
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PMID:Biologically active peptides: prospects for drug development. 610 49

The effects of a number of vasoactive and neurotransmitter substances on lymphocyte traffic were studied by assessing their effects on the release of lymphocytes into primary peripheral (popliteal) nodal efferent lymph of sheep following acute infusion into cannulated afferent nodal lymphatics. In a total of 23 experiments, the output of lymphocytes, small and blast, was increased by serotonin, substance P, bombesin, [met]enkephalin, isoprenaline and phenylephrine and was decreased by vasoactive intestinal peptide (VIP), neurotensin and carbachol. Substances whose actions are modulated by prostaglandins and enhanced by prostaglandin synthesis inhibitors and which elevate blood monocyte and nervous tissue levels of cyclic GMP tended to increase lymphocyte traffic through peripheral lymph nodes in sheep in vivo. The opposite effect tended to be produced by substances whose actions require or are associated with prostaglandins or histamine, and which affect blood monocytic cyclic nucleotide levels by elevation of cyclic AMP or depression of cyclic GMP. Pain and inflammation tended to increase lymphocyte traffic, while analgesics and immunomodulators tended to decrease it.
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PMID:Modification of lymphocyte traffic by vasoactive neurotransmitter substances. 614 65

(1) Capsaicin solution was applied for 15 min around a 1 cm length of sciatic nerve in the mid upper leg of adult rats. (2) Electron microscopic examinations of the nerve in the treated region after 14 days shows no signs of degeneration of either myelinated or unmyelinated fibres attributable to the capsaicin. (3) Fluoride resistant acid phosphatase FRAP disappears from the central terminals of the treated nerve by 7 days. (4) 1.5 mM capsaicin is sufficient to product a complete reduction of FRAP in the spinal cord. (5) The peptides substance P and cholecystokinin (CCK) are markedly depleted in the region of spinal cord terminations of the treated nerve at 14 days. (6) Substance P and CCk are not affected in spinal cord regions other than in the unmyelinated afferent terminal zone. Similarly neurotensin and neurophysin which are not present in afferent fibres are not influenced by capsaicin treatment of the sciatic. (7) It is concluded that there are chemical changes in the spinal cord terminals of fine afferents after local peripheral capsaicin.
Pain 1981 Dec
PMID:Effects of capsaicin applied locally to adult peripheral nerve. II. Anatomy and enzyme and peptide chemistry of peripheral nerve and spinal cord. 617 30

Neurotensin has been demonstrated to be analgesic in rodents. This study used intrathecal injection of neurotensin in unanesthetized mice to evaluate the effect of the peptide at the spinal level on unconditioned behavior. Intrathecal administration of neurotensin produced dose-related inhibition of locomotor activity and of the response elicited by subcutaneous hypertonic saline. The effects of the peptide in the tail flick assay were variable and it produced no inhibition of the behavioral response to intrathecal substance P. The results indicate that neurotensin antinociception at the spinal level does not result from locomotor impairment, may be somewhat selective for chemically induced pain, and may be mediated by a presynaptic action on primary afferent fibers.
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PMID:Antinociceptive action of intrathecal neurotensin in mice. 619 60

Polypeptides are endogenous agents, involved in the regulation of many physiologic functions and the pathogenesis of several diseases. Polypeptide antagonists form a group of new chemical entities which may provide valid therapeutic agents. Some polypeptides (angiotensin, kinins) are released through the action of proteolytic enzymes (renin, kallikreins) and act as hormones or autacoids; others (substance P, neurotensin) are synthetized by nervous cells to serve as neurotransmitters or neuromodulators. The main homeostatic role of the renin-angiotensin system is to uphold high systemic arterial blood pressure. Overproduction of renin and insufficient checking of renin secretion are among the most common causes of arterial hypertension. Several forms of arterial hypertension (neurovascular, idiopathic) benefit from a reduction in renin-angiotensin system activity. This is achieved either through decreasing renin secretion, by inhibiting conversion of angiotensin I into angiotensin II, or through blocking the peripheral actions (at the receptor sites) of angiotensin II. Renin secretion is very significantly reduced by beta-blocking agents (propranolol); conversion of angiotensin I into angiotensin II is inhibited by teprotide, captopril and their derivatives; peripheral actions of angiotensin II are blocked by saralasin. Bradykinin and related agents produce vasodilation, increase vascular permeability and stimulate pain fibers. Kinins thus reproduce the cardinal features of inflammation and are held to be mediators of the inflammatory reaction. The substance P neuropeptide is found in the brain and bowel; it may act as a transmitter of the sensation of pain at the spinal cord and central nervous system sites. Among other effects outside of the brain, substance P is a potent vasodilator and inhibits renin secretion. Neurotensin is a neuropeptide which produces hypothermia, muscular relaxation and analgesia. Outside of the brain, this peptide is involved in the regulation of gastric secretion, intestinal motility and insulin and glucagon secretion. The vasoactive intestinal peptide, found in certain cholinergic nerve endings, is a large peptide which inhibits gastric secretion, intestinal motility and vascular tone.
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PMID:[Polypeptides and antagonists]. 620 6

Neurotensin, a tridecapeptide, has been proposed to have a role in sensory systems, especially those mediating pain. The light microscopic and ultrastructural localization of neurotensin immunoreactivity in neurons of the monkey spinal cord was studied with the aim of examining their synaptic interactions. At the light microscopic level, neurotensin-containing cells were located in laminae II and III and immunoreactive axons and terminals were found in laminae I, II, and III. Neurotensin-positive axons were mostly thin and unmyelinated and their boutons contained both clear and large granular vesicles. Boutons varied considerably in size (1-3 micron) and in their relative content of large granular vesicles, which appeared occasionally in presynaptic locations. In lamina I neurotensin-immunoreactive terminals formed synapses with cell bodies which varied both in size and subcellular features. Some large dendrites in lamina I were contacted by numerous neurotensin-positive axons and also unlabeled terminals. In lamina II boutons with neurotensin immunoreactivity formed synapses mostly with small unlabeled dendrites some of which contained vesicles. The present results together with recent anatomical and physiological findings suggest that spinal cord neurons which contain neurotensin synapse with cells in the superficial dorsal horn that receive either input from primary afferents conveying nociceptive information or form part of the spinothalamic tract, or both. The diversity observed both in the morphology of neurotensin-positive terminals and in their synaptic patterns may indicate that they arise from more than one type of dorsal horn cell.
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PMID:Ultrastructural localization of immunoreactive neurotensin in the monkey superficial dorsal horn. 637 45

Thyrotropin releasing hormone (TRH) interacts with both opioid and non-opioid systems in mediating hypothermic, hypoactive, cataleptic, respiratory and analgesic effects. While TRH neither antagonizes opioid analgesia nor alters pain thresholds itself, it blocks neurotensin analgesia. Different forms of pain-inhibition in rats can be activated by selectively altering the parameters of shock: while analgesia induced by 20 inescapable tail-shocks is not reversed by naltrexone, exposure to 60 or 80 shocks does elicit naltrexone-reversible analgesia. The first experiment examined whether intracerebroventricular administration of TRH (0, 10, or 50 micrograms) would alter the elevations in tail-flick latencies in rats induced by 20 or 80 foot shocks and found that TRH significantly lengthened the duration and magnitude of analgesia induced by 20 and 80 foot shocks in a dose-dependent manner. The second experiment extended these findings to the writhing test, a visceral pain test. While the number and duration of writhes of vehicle-treated rats exposed to 80 foot shocks failed to differ from baseline values. TRH (50 micrograms)-treated rats exposed to 80 foot shocks displayed significant decreases in the number and duration of writhes. The third experiment indicated that the differential effects of naltrexone upon analgesia induced by 20 or 80 tail shocks were not apparent when foot shocks were employed, precluding a definitive statement that TRH may be involved in the modulation of both opioid and non-opioid forms of analgesia.
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PMID:Potentiation of foot shock analgesia by thyrotropin releasing hormone. 643 31

Behavioral and electrophysiological techniques were used to examine the effects of local injections of neurotensin (NT) into the periaqueductal gray (PAG). The results of the behavioral experiments showed that injection of NT into the PAG produced dose-dependent analgesia that lasted for as long as 60 min and was not blocked by naloxone. However, electrolytic lesions of the nucleus raphe magnus (NRM) and its surrounding area, abolished the analgesic effect of NT. Electrophysiological experiments indicated that micro-pressure application of NT onto neurons in the PAG had a predominantly excitatory effect. Furthermore, it was shown that injection of NT into the PAG produced excitation of the NRM neurons. It is concluded that NT produces its analgesic effect by excitation of PAG neurons which leads to activation of the pain inhibitory system that originates from the NRM and its surrounding areas in the medulla.
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PMID:A mechanism for the analgesic effect of neurotensin as revealed by behavioral and electrophysiological techniques. 651 91

Given an indication for surgery in patients with chronic pancreatitis, such as distal common bile duct obstruction, duodenal stenosis, or dilated pancreatic duct with stones and congestion, the surgeon must decide the type of operation to perform. A duodenopancreatectomy, the Whipple procedure, is widely considered to be the gold standard. It is highly effective in relieving pain and eliminating the structural abnormalities noted above. Duodenum-preserving resection of the head of the pancreas (DPRHP) seems to be an attractive alternative to pancreaticoduodenectomy (PD) in the treatment of chronic pancreatitis. In a clinical prospective randomized trial the efficiency of both operative methods was investigated. Between 7/1987 and 12/1993 43 patients were randomly assigned to undergo either a Whipple procedure (n = 21) or DPRHP (n = 22). Data on postoperative course, mortality, and postoperative morbidity were compiled. As concerns long-term results, postoperative hormonal status (insulin, neurotensin, cholecystokinin, gastrin) was checked, basal and stimulated with a standardized meal, using standard hormonal assay kits. All patients with PD survived, whereas one with DPRHP died from peritonitis. Patients with DPRHP had a significant more rapid convalescence (16.5 vs. 21.7 days). The range for postoperative follow-up is from 36 months to 5.5 years. In the DPRHP group 18 patients are in good condition. Two had diabetes and one developed carcinoma. In the PD group one died from hepatic coma, 14 are in good condition and 6 developed diabetes. All gained body weight with an average of 6.4 vs. 4.9 kg, DPRHP vs. PD. A difference between DPRHP and PD was obvious for the postoperative hormonal status. Results are satisfactory in both groups. For patients with DPRHP however, we see a quicker convalescence and a significant benefit as concerns postoperative hormonal status.
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PMID:[Pancreatic function and quality of life after resection of the head of the pancreas in chronic pancreatitis. A prospective, randomized comparative study after duodenum preserving resection of the head of the pancreas versus Whipple's operation]. 763 46

In order to establish the ferret as an animal model for studies of trigeminal pain, we describe the cytoarchitecture and neurochemistry of the trigeminal nuclear complex in the ferret and compare them to those of the cat and rat. The complex was divided as previously described, but the ferret differed in the extent of the nuclear boundaries. The neuroanatomical istribution of substance P-, calcitonin gene-related peptide-, galanin-, enkephalin-, serotonin-, somatostatin-, neuropeptide Y-, and neurotensin-immunoreactivity was determined throughout the rostrocaudal extent of the complex. In subnucleus caudalis, substance P-, calcitonin gene-related peptide-, enkephalin-, serotonin-, somatostatin-, neuropeptide Y-, and galanin-immunoreactivity was densest in laminae I and II. In subnucleus interpolaris, immunoreactivity for all the above neurochemicals was most dense along the lateral border and the ventral third of the caudal part of the subnucleus. Enkephalin-immunoreactive cell bodies were present in subnucleus caudalis and interpolaris. In subnucleus oralis, labelling for substance P, calcitonin gene-related peptide, galanin, enkephalin, and serotonin was most prominent in the dorsomedial part of the subnucleus. Somatostatin-immunoreactive cell bodies were distributed throughout the spinal nucleus. Labelling of serotonin, substance P, calcitonin gene-related peptide, galanin, enkephalin, and somatostatin was present in the main sensory nucleus. The motor nucleus contained fibers immunoreactive for substance P, enkephalin, serotonin and neuropeptide Y, and cell bodies immunoreactive for calcitonin gene-related peptide. The majority of neurotensin-immunoreactivity was found at the level of subnucleus caudalis, where it was densest in the trigeminal extension of the lateral cervical nucleus. The distribution of peptides in this species throughout the spinal nucleus is consistent with the notion that all the subnuclei may be involved in the processing of nociceptive inputs.
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PMID:Trigeminal nuclear complex of the ferret: anatomical and immunohistochemical studies. 768 53


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