Bradykinin antagonizes morphine-induced analgesia in rats.
The intraventricular injection of 5 micrograms of bradykinin or Met-Lys-bradykinin in rats antagonized the increase in nociception threshold induced by morphine (5 micrograms i.c.v. or 10 mg/kg i.p.) in the tail flick test. The effect of the two kinins was prevented by atropine (30 mg/kg i.p.). The results suggest that bradykinin counteracts opiate activity in the central nervous system by enhancing acetylcholine release.
D000109:Acetylcholine / Q000378:metabolism; D000700:Analgesics / Q000037:antagonists & inhibitors*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology*; D009020:Morphine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D000700:Analgesics; C018103:bradykinin, Met-Lys-; D009020:Morphine; D001285:Atropine; D000109:Acetylcholine; D001920:Bradykinin