Diazepam-induced release of opioid activity in the rat brain.
Acute intravenous injection of diazepam (2.5 mg/kg) in rats resulted in a moderate (2-fold) increase in pain threshold, as measured by the 'vocalization test'. This effect was not antagonized by naloxone (10 mg/kg, i.p.). However, pretreatment of the animals with the enzyme-inhibitor, bacitracin (50 micrograms, i.c.v.), dramatically enhanced the diazepam-induced antinociception. This increased effect was partially antagonized by naloxone, indicating an opioid-mediated mechanism as involved and further supports the hypothesis that benzodiazepine application may release opioid peptides in restricted areas of the CNS.
D000700:Analgesics; D000818:Animals; D001414:Bacitracin / Q000008:administration & dosage; D001921:Brain / Q000378:metabolism*; D003975:Diazepam / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004745:Enkephalins / Q000378:metabolism*; D008297:Male; D010146:Pain / Q000188:drug therapy*; D051381:Rats; D011919:Rats, Inbred Strains; D012684:Sensory Thresholds
D000700:Analgesics; D004745:Enkephalins; D001414:Bacitracin; D003975:Diazepam