Cholinergic influences on opioids activity in rats.
The influence of cholinergic and anticholinergic agents on the catalepsy and antinociceptive action of morphine, codeine, fentanyl and pentazocine was studied in rats. Anticholinergic drugs scopolamine (3 and 6 mg/kg) and slightly atropine (1 mg/kg) enhanced morphine-induced catalepsy. Benztropine did not change this action of morphine. Cholinergic physostigmine (0.2 and 0.4 mg/kg) showed marked and dose-dependent antagonism toward morphine catalepsy, but pilocarpine, in doses of 2 and 4 mg/kg, failed to influence it. Catalepsy induced by codeine and fentanyl was nearly not influenced by cholinergic and anticholinergic agents. In the hot plate test, cholinergic influences on antinociceptive activity of analgesics are slight, but sometimes it may be observed the similar interaction as in morphine catalepsy: anticholinergic agents enhance, and cholinergic agents antagonize these effects. Present results indicate that some cholinergic and anticholinergic agents influence morphine catalepsy, and this influence is opposite to that observed in neuroleptic-induced catalepsy. Failure of the cholinergic influences on fentanyl- and codeine-induced catalepsy suggests that the mechanisms of cataleptogenic activity of morphine and other analgesics are not the same.
D000698:Analgesia; D000818:Animals; D002375:Catalepsy / Q000139:chemically induced; D003061:Codeine / Q000494:pharmacology; D005283:Fentanyl / Q000494:pharmacology; D006801:Humans; D008297:Male; D009294:Narcotics / Q000494:pharmacology*; D010275:Parasympathetic Nervous System / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects
D009294:Narcotics; D005283:Fentanyl; D003061:Codeine