Antagonism of dermorphin-induced catalepsy with naloxone, TRH-analog CG3703 and the benzodiazepine antagonist, Ro 15-1788.
Intracerebroventricular (i.c.v.) administration of the highly selective opiate mu-receptor agonist, dermorphin, produced dose-dependent catalepsy in conscious rats. The cataleptic effect of dermorphin was abolished by pretreatment (intraperitoneal, i.p.) with the opiate-antagonist naloxone (5 mg/kg), thyrotropin-releasing hormone analog CG3703 (1 mg/kg) or the benzodiazepine-antagonist Ro 15-1788 (5 mg/kg) whereas pretreatment with the benzodiazepine alprazolam (1 mg/kg) potentiated the cataleptic effect of dermorphin. When given to cataleptic rats, naloxone and CG3703, but not Ro 15-1788, reversed the dermorphin-induced catalepsy. The data suggest an involvement of benzodiazepine receptors in the induction of catalepsy mediated by opioid mu-receptors. Other opioid-modulating neuronal systems, antagonized by CG3703, may be involved in maintaining the dermorphin-induced cataleptic state.
Paakkari
P
P
Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.
Feuerstein
G
G
D000525:Alprazolam / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors* / Q000633:toxicity; D000818:Animals; D002375:Catalepsy / Q000139:chemically induced*; D005442:Flumazenil / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009842:Oligopeptides / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000633:toxicity; D018847:Opioid Peptides; D051381:Rats; D011919:Rats, Inbred Strains; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology
D000701:Analgesics, Opioid; D009842:Oligopeptides; D018847:Opioid Peptides; C030058:dermorphin; C031926:montirelin; D009270:Naloxone; D005442:Flumazenil; D013973:Thyrotropin-Releasing Hormone; D000525:Alprazolam