Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0344307 (analgesia)
 28,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A form of electrically-induced analgesia known as electroacupuncture was administered to rats bilaterally at the point "Huan-tiao." Compared with untreated rats, treated rats showed altered pain thresholds characterized as low, intermediate, and high. From immunocytochemical studies, the spinal cords taken from the treated rats exhibited differences in immunoreactivity for substance P (SP), methionine- and leucine-enkephalins (ME and LE respectively). By densitometry, the altered levels of immunoreactive (IR) peptides correlated with the pain thresholds in specific ways. That is, high pain threshold correlated with the visualization of increased IR-SP adn IR-LE within neuronal processes throughout the dorsal horn substantia gelatinosa. In the same specimens, decreased IR-ME could be seen. In contrast, low pain threshold correlated with decreased IR-SP and IR-ME. IR-LE showed a concomitant decrease in the medial substantia gelatinosa region, and slight, insignificant changes laterally. The data suggest that different degrees of analgesia induced by electroacupuncture result from the variable release of SP, ME, and LE in spinal regions associated with nociception. In terms of current models of pain processing, the data do not entirely support an axo-axonic interaction between enkephalin interneurons and SP terminals. Some modifications and an alternative model are considered.
 ...
PMID:Alterations of immunoreactive substance P and enkephalins in rat spinal cord after electroacupuncture. 241 27

Determinations were made of the effects of the calcium channel blockers, nifedipine and verapamil, on the antagonistic effects of FMRFamide (Phe-Met-Arg-Phe-NH2) and naloxone on morphine- and immobilization-induced opioid analgesia in mice. Intraperitoneal (i.p.) administrations of the calcium channel antagonists significantly reduced the inhibitory effects of intracerebroventricular (i.c.v.) FMRFamide, but had no effects on i.p. or i.c.v. naloxone-mediated inhibition of either morphine- or immobilization-induced analgesia. These results suggest that the antagonistic effects of FMRFamide, (or other endogenous FMRFamide-like peptides) on both opiate- and opioid-mediated analgesia in mice may involve alterations in the functioning of calcium channels.
 ...
PMID:Calcium channel blockers inhibit the antagonistic effects of Phe-Met-Arg-Phe-amide (FMRFamide) on morphine- and stress-induced analgesia in mice. 244 May 27

Sulfated cholecystokinin octapeptide (CCK-8; Asp-Tyr-SO3H-Met-Gly-Trp-Met-Asp-Phe-NH2) produced analgesia in mice when administered i.c.v. and tested in the acetic acid-induced writhing assay. The ED50 was found to be 0.03 nmol/mouse which was about 3, 24 and 714 times more potent than morphine. [D-Pen2,D-Pen5]enkephalin and U50,488H [trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrolidinyl)cyclohexyl] benzeneacetamidel], respectively. When administered i.t., CCK-8 produced partial analgesia of up to 22 to 23% at low doses ranging from 15 to 60 ng/mouse and hyperalgesia at doses over 120 ng/mouse. Naloxone, an opioid antagonist, inhibited the analgesia induced by CCK-8 (i.c.v. and i.t.) but potentiated hyperalgesia induced by CCK-8 (i.t.). Apparent pA2 value for CCK-8 (i.c.v.) against naloxone (s.c.) was 5.88 which was significantly different from those for morphine-naloxone and U50,488H-naloxone but was not significantly different from that for [D-Pen2,D-Pen5]enkephalin-naloxone. Studies using highly selective opioid antagonists showed that CCK-8-induced analgesia was significantly antagonized by the delta receptor antagonist, ICI154,129 [(Allyl)2-Tyr-gly-gly-psi-(CH2S)-Phe-Leu] but not by beta-funaltrexamine, a highly selective mu receptor antagonist or nor-binaltorphimine, a highly selective kappa receptor antagonist. Opioid receptor binding study using [3H]-[D-Ala2,D-Leu5]enkephalin (+unlabeled [D-Ala2,MePhe4,Gly-ol5]enkephalin) in mouse brain membrane preparations revealed that there were no changes in the maximum binding or Kd of delta opioid binding sites in the presence of CCK-8 (1 microM) in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Indirect involvement of delta opioid receptors in cholecystokinin octapeptide-induced analgesia in mice. 255 28

The involvement of delta opioid receptors in supraspinal analgesia was investigated. With this aim, opioids that produced analgesia in the tail immersion test were administered i.c.v. to mice a few minutes before the irreversible antagonist, beta-funaltrexamine (beta-FNA). Protection of the respective analgesic effects from beta-FNA blockade was obtained when evaluated 24 h later. Moreover, mu ligands protected the analgesia evoked by ED50s of morphine, [D-Ala2,N-Me-Phe4,Met-(o)5-ol]enkephalin (FK 33-824), [D-Ala2,N-Me-Phe4,Gly-ol5]enkephalin (DAGO) and human beta-endorphin at doses (ED50s) lower than those required for delta ligands (approximately ED90s) to reach a similar protection. delta Preferential ligands effectively protected the analgesia induced by ED50s of [D-Ala2,D-Leu5]enkephalin (DADLE), [D-Thr2,Leu5]enkephalin-Thr6 (DTLET) and [D-Pen2,D-Pen5]enkephalin (DPDPE) from the beta-FNA-deteriorating effect. FK 33-824 and DAGO also provided good protection of the analgesia elicited by these delta ligands whereas morphine protected much less. Binding studies after i.c.v. injection of beta-FNA showed that its alkylating effect on opioid receptors was restricted to periventricular areas. In PAG, where the mu/delta receptor ratio is about 10, [3H]DADLE specific binding was still present after ED50s of DPDPE, DAGO, morphine and DADLE as protecting agents. [3H]Dihydromorphine [( 3H]DHM) binding was well protected by ED90s of morphine and DAGO, and to a lesser extent by DPDPE and DADLE. These results suggest that delta ligands, after binding to delta receptors, also need to act upon mu receptors to produce high levels of supraspinal analgesia in the tail immersion test.
 ...
PMID:Evaluation of delta receptor mediation of supraspinal opioid analgesia by in vivo protection against the beta-funaltrexamine antagonist effect. 256 40

The concentrations of endogenous opiates (beta-endorphin, methionine-enkephalin, leucine-enkephalin) in the spinal fluid and arterial blood plasma has been studied in 16 dogs, using the model of acute pain stimulation under electroacupuncture analgesia (EAA). It has been shown that pain stimulation under EAA is accompanied by a significant increase in methionine-enkephalin++ and leucine-enkephalin concentrations (by 244 and 69.4%, respectively) in the spinal fluid. beta-endorphin level tends to increase. There is also a trend towards the reduction in beta-endorphin and methionine-enkephalin concentrations in the arterial blood plasma, which is indicative of effective antinociceptive stimulation of the endogenous opiate system. However, by the end of the first hour a decrease of methionine-enkephalin and leucine-enkephalin levels in the spinal fluid was paralleled by a trend towards beta-endorphin and methionine-enkephalin increase and a significant leucine-enkephalin increase in arterial blood plasma, which can account for the exhaustion of the opiate system.
 ...
PMID:[Changes in the concentration of endogenous opiates in the blood and cerebrospinal fluid during acute painful stimuli and protective electroacupuncture analgesia]. 262 35

I.c.v. injection of 1 nmol N-ethylmaleimide (NEM) into mice interfered with opioid-induced supraspinal analgesia, as assessed in the warm water tail-flick test. This effect of NEM was long-lasting (more than 3 days), non-competitive and differentially inhibited by the opioids studied. The analgesia induced by [D-Ala2,D-Leu5]enkephalin (DADLE), [D-Ala2,Met5]enkephalinamide (DAME) and [D-Pen2,D-Pen5]enkephalin (DPDPE) was greatly reduced in NEM-treated mice. The antinociception elicited by [D-Ala2,N-MePhe4,Gly-ol5]enkephalin (DAGO) was also impaired although to a lesser extent. In contrast, the activity of morphine and etorphine remained unchanged. NEM-sensitive opioids coadministered with morphine antagonized the analgesia elicited by the alkaloid in NEM-treated mice. The administration of naltrexone or DADLE, DAGO, [D-Ala2,N-MePhe4,Met-(O)5-ol]enkephalin (FK-33824) and morphine in doses equivalent to the ED90 doses for inducing analgesia, a few minutes before NEM prevented it from interfering with DADLE-elicited supraspinal analgesia when evaluated 24 h later. In contrast, the selective delta antagonist, ICI 174864, did not protect the DADLE-induced analgesia against the effect of NEM. We suggest that NEM produced its effect by acting upon a site that appears to be distal to the receptor binding site, presumably located on the guanine nucleotide binding regulatory proteins, Gi/Go. Therefore, these transducer proteins might play a key role in the effects displayed by opioids when acting via the mu receptor-Gi/Go complexes.
 ...
PMID:Intracerebroventricular N-ethylmaleimide differentially reduces supraspinal opioid analgesia in mice. 267 63

Two peptides that are structurally related to the molluscan tetrapeptide Phe-Met-Arg-Phe-NH2 (FMRF-NH2) were recently isolated from bovine brain extract (Yang et al.: Proc. Natl. Acad. Sci. USA 82:7757-7761, '85). These peptides have an attenuating effect on morphine-induced analgesia when injected intracerebroventricularly in rats. Antisera against the two peptides--an octapeptide, Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2 (F8F-NH2), and an octadecapeptide, Ala-Gly-Glu-Gly-Leu-Ser-Ser-Pro-Phe-Trp-Ser-Leu-Ala-Ala-Pro-Gln-Arg-Phe- NH2 (A18F-NH2)--were raised in rabbits and characterized with standard radioimmunoassay and immunohistochemical blocking controls. This study was aimed at localizing neurons in the rat brain that contain immunoreactivity for these peptides. Cryostat sections of normal and colchicine-treated Sprague-Dawley rat brains were incubated with the specific antisera and the immunoreactivity was visualized by the PAP or the FITC method. Immunoreactive neurons were detected in the hypothalamus and nucleus of the solitary tract. Relatively dense networks of fibers and terminals were observed in the lateral parabrachial nucleus and in the nucleus of the solitary tract. Fibers and terminals were also seen in the lateral septum, amygdala, hypothalamus, neurohypophysis, thalamus, periaqueductal gray, and several medullary nuclei. In these areas the immunoreactivity was abolished when the antisera were incubated with the corresponding synthetic peptides F8F-NH2 and A18F-NH2. Preincubation of the antisera with neuropeptide Y (NPY) did not affect the staining. The results suggest that there are neurons in the rat brain that contain F8F-NH2- and A18F-NH2-like peptides. The neuronal system described here may have a role in the regulation of autonomic functions, such as hypothalamic control and respiratory functions. The neuronal connections of the cells containing F8F-NH2- and A18F-NH2-like peptides remain to be studied.
 ...
PMID:Immunohistochemical distribution and partial characterization of FLFQPQRFamidelike peptides in the central nervous system of rats. 279 21

Seven women undergoing abdominal hysterectomy under halothane and nitrous oxide analgesia had plasma samples taken before, during and after surgery for assay of adrenocorticotrophin (ACTH), beta-endorphin, beta-lipotrophin and methionine (Met)-enkephalin immunoreactivity. Plasma ACTH, beta-endorphin and beta-lipotrophin all rose in parallel from the start of surgery and were unaffected by postoperative opiate analgesia. Plasma Met-enkephalin concentrations did not change significantly during the course of the surgery and immediate post-operative period, although the variance of the samples increased at the time of the first skin incision. These data indicate that the stress of surgery and post-operative pain, while producing marked elevations of proopiomelanocortin-derived peptides, are not associated with changes in plasma Met-enkephalin. These data exclude a role for circulating Met-enkephalin in the modulation of surgical pain but do not exclude such a role for beta-endorphin.
 ...
PMID:The effect of surgery on plasma beta-endorphin and methionine-enkephalin. 285 64

The effects of i.c.v. administration of the peptide FMRFamide (Phe-Met-Arg-Phe-NH2), as well as i.p. injections of PLG (Pro-Leu-Gly-NH2) and the opiate antagonist, naloxone, on immobilization-induced analgesia and locomotor activity were examined in CF-1 and C57BL strains of mice. Both naloxone (1.0 mg/kg) and FMRFamide (0.10-1.0 microgram) blocked the experimentally induced analgesia and activity, whereas PLG (0.10-10 mg/kg) suppressed only analgesia. These results indicate that FMRFamide (or FMRFamide-like neuropeptides) and PLG may function as differential antagonists of the behavioral and physiological consequences of endogenous opioid activation.
 ...
PMID:Inhibitory influences of FMRFamide and PLG on stress-induced opioid analgesia and activity. 287 3

The hyperphagia and obesity induced by ventromedial hypothalamic (VMH) electrolytic lesions in female rats were associated with a 70-94% decrease in the level of beta-endorphin (beta-E) in the hypothalamus and other regions of brain, but not in the pituitary. Dynorphin (Dyn) and methionine-enkephalin (ME) levels were also decreased. Rats with VMH lesions were less sensitive to the inhibitory effect of naloxone on their food-intake. Mice injected with gold thioglucose (GTG) also showed a decrease in the hypothalamic content of beta-E and Dyn and exhibited 30% less analgesia compared to control mice after cold swim stress.
 ...
PMID:Effect of electrolytic and chemical ventromedial hypothalamic lesions on food intake, body weight, analgesia and the CNS opioid peptides in rats and mice. 289 79


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>