Effect of metergoline, fenfluramine, and 8-OHDPAT on catalepsy induced by haloperidol or morphine.
The influences of the indirect serotonin agonist fenfluramine (5; 10 mg/kg s.c.), the serotonin antagonist metergoline (5; 10 mg/kg s.c.) and the 5-HT1A agonist 8-OHDPAT (0.1; 0.2; 0.46 mg/kg s.c.) on haloperidol-induced catalepsy in rats or mice and on morphine-induced catalepsy in rats were studied. Morphine-induced catalepsy was enhanced by fenfluramine and attenuated by metergoline, whereas neither fenfluramine nor metergoline had any effect on haloperidol-induced catalepsy. 8-OHDPAT strongly antagonised catalepsy induced by morphine or haloperidol. We conclude that serotonergic transmission plays a major role in effectuating morphine catalepsy but not in effectuating haloperidol catalepsy. The antagonistic effect of 8-OHDPAT suggests a secondary, modulating role for 5-HT1A receptor mediated events in both types of catalepsy.
Broekkamp
C L
CL
Department CNS Pharmacology, Organon International B.V., Oss, The Netherlands.
Oosterloo
S K
SK
Berendsen
H H
HH
van Delft
A M
AM
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D002375:Catalepsy / Q000139:chemically induced*; D004347:Drug Interactions; D005277:Fenfluramine / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D008711:Metergoline / Q000494:pharmacology; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
D013764:Tetrahydronaphthalenes; D008711:Metergoline; D005277:Fenfluramine; D012701:Serotonin; D009020:Morphine; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D006220:Haloperidol