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)

There is evidence suggesting that the endogenous tetrapeptide, Tyr-MIF-1 (Tyr-Prol-Leu-Gly-amide), has antagonistic or modulatory effects on opioid-mediated analgesia. There is also substantial evidence for sex differences in opioid effects, whereby male rodents display greater levels of opioid-mediated analgesia than females. In the present study, determinations were made of the effects of Tyr-MIF-1 on morphine- and restraint stress-induced opioid analgesia in adult male and female deer mice, Peromyscus maniculatus. Intraperitoneal treatment with Tyr-MIF-1 (0.10-10 mg/kg) reduced morphine- and stress-induced analgesia in both male and female mice, with Tyr-MIF-1 having markedly greater antagonistic effects in male than female mice. These results indicate that there are sex differences in the modulatory (antiopiate) effects of Tyr-MIF-1 on opioid-mediated analgesia.
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PMID:Sex differences in the effects of Tyr-MIF-1 on morphine- and stress-induced analgesia. 136 81

It has been demonstrated that cimetidine blocks the effect of naloxone on footshock-induced analgesia. To study the effect of cimetidine on the antiopiate properties of an endogenous peptide Tyr-MIF-1, the opiate form of intermittent footshock-induced analgesia was elicited in the rat. The nociceptive responses were determined using the hot-plate test (52.5 degrees C). Intraperitoneal pretreatment with cimetidine (100 mg/kg) or chlorpheniramine maleate (20 mg/kg) did not affect the footshock-induced analgesia, and did not change the antagonizing effect of Tyr-MIF-1 (0.2 mg/kg) on this model of antinociception. It is concluded that cimetidine and chlorpheniramine maleate do not change the antagonizing effect of Tyr-MIF-1 on the opiate form of intermittent footshock-induced analgesia.
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PMID:Cimetidine does not change the effect of Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) on the opiate form of footshock-induced analgesia. 168 Feb 11

Previous studies have shown that some of CNS actions of an endogenous peptide Tyr-MIF-1, are mediated by dopamine (DA) receptors. To study the effect of DA receptor blockade on the antiopiate properties of Tyr-MIF-1, the opiate form of footshock-induced analgesia was elicited in the rat. The nociceptive responses were determined using the hot-plate test (52.5 degrees C). Intraperitoneal pre-treatment with haloperidol (500 micrograms/kg), SCH 23390 (150 micrograms/kg), or spiroperidol (150 micrograms/kg) potentiated the antinociceptive effect of the footshock and blocked the antagonistic action of Tyr-MIF-1 (200 micrograms/kg and 2.0 mg/kg). A dose of haloperidol too small to potentiate the antinociceptive effect of the footshock (100 micrograms/kg) was still able to block the action of Tyr-MIF-1 (200 micrograms/kg). The results suggest that activation of DA receptors mediates the antagonizing effect of Tyr-MIF-1 on the opiate form of footshock-induced analgesia in the rat.
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PMID:Dopamine receptor antagonists block the effect of Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) on the opiate form of footshock-induced analgesia. 168 56

The effect of Pro-Leu-Gly-NH2 (MIF) on the acquisition of tolerance to morphine-induced antinociception and its efficacy as a cue predictive of morphine administration was examined. Daily administration of MIF prior to morphine injection did not attenuate the acquisition of tolerance to the antinociceptive properties of morphine, as measured by the latency to hindpaw lick in a hot-plate test of analgesia. When the animals were tested 72 hr later without MIF pretreatment, they appeared to lose tolerance, as indicated by longer latencies to paw lick. These data suggest that in some situations MIF may interfere with the acquisition of tolerance by acting as a cue that reliably predicts the antinociceptive properties of morphine.
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PMID:Pro-Leu-Gly-NH2 serves as a conditioned stimulus in the acquisition of conditioned tolerance. 256 16

The effects of body rotation in a horizontal plane and various opiate antagonists on the nociceptive responses of a day-active microtine rodent, the meadow vole, Microtus pennsylvanicus, were examined. Intermittent rotation (70 rpm, schedule of 30 sec on, 30 sec off) for 30 min induced significant analgesic responses in the voles for 15 min after rotation. These increases in thermal response latency were blocked by intraperitoneal pretreatment with either naloxone or the irreversible mu opiate receptor antagonist beta-funaltrexamine (beta-FNA; 10 mg/kg; 24 hr pretreatment). This antagonistic effect of beta-FNA indicates mu opioid involvement in the mediation of rotation-induced analgesia. The antiopiate peptides MIF-1 (Pro-Leu-Gly-NH2) and Tyr-MIF-1 also significantly reduced, though did not completely block, body rotation-induced opiate analgesia. This suggests that Tyr-MIF-1 and MIF-1 have significant antagonistic effects on mu opioid systems that are involved in the mediation of stress (rotation)-induced analgesia.
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PMID:Differential inhibitory effects of MIF-1, Tyr-MIF-1, naloxone and beta-funaltrexamine on body rotation-induced analgesia in the meadow vole, Microtus pennsylvanicus. 257 Nov 38

The effects of Prolyl-leucyl-glycinamide (PLG, MIF-1) and the exogenous opiate antagonist naloxone, on aggressive interactions and defeat-induced analgesia were examined in male mice. Both substances reduced the number of bites required to obtain defeat in subordinate mice during aggressive encounters as well as blocking the subsequent defeat-induced analgesia. These results suggest that MIF-1 may function as an endogenous opioid antagonist and have an inhibitory influence on aggression.
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PMID:Prolyl-leucyl-glycinamide reduces aggression and blocks defeat-induced opioid analgesia in mice. 286 8

Forced swimming in warm or cold water can lead to immobility and analgesia in mice. In this report we demonstrate that the peptide MIF-1 (Pro-Leu-Gly-NH2) was able to attenuate the analgesia induced by swimming in warm water, but not that induced by swimming in cold water. In addition, we show that the analgesia and the immobility may be differentially mediated since MIF-1 was able to reduce the immobility at doses different from those necessary to reduce the analgesia. These results confirm previous research indicating that MIF-1 may act as an anti-opiate and further demonstrate that MIF-1 affects analgesia induced by stress.
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PMID:MIF-1 antagonizes warm-, but not cold-water stress-induced analgesia: dissociation from immobility. 287 47

The effects of prolyl-leucyl-glycinamide (MIF-1, PLG), tyrosine-prolyl-leucyl-glycinamide (Tyr-MIF-1, YPLG) and the exogenous opiate antagonist, naloxone, on aggressive interactions and defeat-induced analgesia were examined in male mice. All three substances reduced the number of bites required to obtain defeat in subordinate mice during aggressive encounters, as well as blocking subsequent defeat-induced analgesia. Tyr-MIF-1 had significantly greater inhibitory effects than MIF. These results suggest that both MIF and Tyr-MIF-1 may function as endogenous opioid antagonists and have inhibitory influences on aggression, with the antagonistic effects of Tyr-MIF-1 being more potent than those of MIF-1.
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PMID:Inhibitory influences of MIF-1 (PLG) and Tyr-MIF-1 (YPLG) on aggression and defeat-induced analgesia in mice. 288 93

The effects of prolyl-leucyl-glycinamide (MIF-1, PLG), tyrosine-prolyl-leucyl-glycinamide (Tyr-MIF-1, YPLG) and naloxone on morphine and warm and cold stress-induced increases in the latency of the thermal (40 degrees C hot plate) avoidance behaviors of the terrestrial snail, Cepaea nemoralis, were examined. All three substances blocked the morphine- and warm stress-induced opioid analgesia, while having no effects on non-opioid cold stress-induced analgesia. Tyr-MIF-1 had a significantly greater inhibitory effect than MIF-1. These results indicate that MIF-1 and Tyr-MIF-1 antagonize the antinociceptive effects of exogenous opiates and opioid-mediated analgesia in snails in a manner analogous to that described for mammals. This raises the possibility of an evolutionary conservation of functional opioid antagonists.
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PMID:MIF-1 and Tyr-MIF-1 antagonize morphine and opioid but not non-opioid stress-induced analgesia in the snail, Cepaea nemoralis. 288 31

Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2), a biologically active brain peptide, has previously been shown to antagonize the analgesia induced by morphine. In this report experiments are described in which mice were tested on the hot-plate in three models of antinociception - shock, novel environment, and warm-water swim - after the administration of various doses of Tyr-MIF-1 without any exogenous opiates. The peptide reduced the antinociception produced by all three methods of inducing endogenous antinociception. These results add further support for the existence of peptides like Tyr-MIF-1 that act as opiate antagonists.
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PMID:Tyr-MIF-1 attenuates antinociceptive responses induced by three models of stress-analgesia. 288 5


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