Effect of diphenylhydramine on the Tyr-MIF-1 antinociception in rats.
Tyr-MIF-1 is a representative of the MIF's family of endogenous peptides. It has been isolated from bovine hypothalamus and human parietal cortex that suggests its involvement in nociception. Tyr-MIF-1 can bind to the mu-receptors as well as to its specific non-opiate receptors in the brain. Data in the literature rise the idea that histamine (HA), a well known nociceptive agent, and Tyr-MIF-1 might have a common pathway in their effects on nociception. We tested that possibility by investigation of the combined action of diphenhydramine (DPH, an H (1) -antagonist) and Tyr-MIF-1 on nociception. The changes in the nociceptive effects were examined in the male Wistar rats by the Randall-Sellito paw-pressure (PP) and the tail-flick (TF) tests. Tyr-MIF-1 in a dose of 1 mg/kg exerted strong naloxone-reversible analgesic effects. DPH (100 microg/kg, i.p.) had an antinociceptive action, too. The co-administration of Tyr-MIF-1 and DPH enhanced the antinociceptive effect, as compared to DPH (PP) and to TYR-MIF-1 alone (TF). These effects were reversed when methylene blue (MB, 500 microg/rat) was applied 1h before the combination. However, naloxone (1 mg/kg, i.p.) only slightly affected the antinociceptive effect of DPH and TYR-MIF-1, compared to that of MB. The results obtained confirmed the hypothesis that cyclic nucleotides are involved in the realization of nociceptive effects of both HA and Tyr-MIF-1.
Bocheva
A
A
Institute of Physiology Bulgarian Academy of Sciences, Sofia, Bulgaria. bocheva@iph.bio.bas.bg
Zamfirova
R
R
Pajpanova
T
T
Todorov
S
S
Georgieva
M
M
Golovinsky
E
E
D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004155:Diphenhydramine / Q000008:administration & dosage / Q000494:pharmacology*; D004338:Drug Combinations; D006614:Hindlimb; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D006358:Hot Temperature; D007274:Injections, Intraperitoneal; D009075:MSH Release-Inhibiting Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000502:physiology; D008297:Male; D009270:Naloxone / Q000008:administration & dosage; D009292:Narcotic Antagonists; D051381:Rats; D017208:Rats, Wistar; D013623:Tail
D000700:Analgesics; D004338:Drug Combinations; D006634:Histamine H1 Antagonists; D009292:Narcotic Antagonists; D009270:Naloxone; C036930:tyrosyl-prolyl-leucyl-glycinamide; D004155:Diphenhydramine; D009075:MSH Release-Inhibiting Hormone