Effects of alpha-flupenthixol and naloxone on CRF-induced locomotor activation.
Corticotropin-releasing factor injected intracerebroventricularly in a dose of 1 microgram produced a prolonged locomotor activation (3 h) in rats previously habituated to the test cage environment. This activation was reversed by alpha-flupenthixol (intraperitoneally), a dopamine receptor antagonist, only at cataleptic doses and not at all by naloxone (subcutaneously) in doses of 0.02-5.0 mg/kg. The effective dose 50% (ED50) for the alpha-flupenthixol reversal of locomotor activity induced by corticotropin-releasing factor was 0.13 mg/kg; similar to the 0.14 mg/kg ED50 needed to reverse the locomotor activation produced by caffeine (10 mg/kg s.c.). The ED50 necessary to reverse amphetamine (0.75 mg/kg s.c.) locomotion with this drug was 0.07 mg/kg. The results suggest that the corticotropin-releasing factor acts independently of direct activation of the dopamine or opioid peptide systems.
D000818:Animals; D001143:Arousal / Q000187:drug effects; D001921:Brain / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D003913:Dextroamphetamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005475:Flupenthixol / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology*; D011292:Premedication; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects; D013892:Thioxanthenes / Q000494:pharmacology*
D011954:Receptors, Dopamine; D011957:Receptors, Opioid; D013892:Thioxanthenes; D009270:Naloxone; D002110:Caffeine; D003346:Corticotropin-Releasing Hormone; D005475:Flupenthixol; D003913:Dextroamphetamine