Oxytocin potently enhances novelty-induced grooming behavior in the rat.
Intracerebroventricular (i.c.v.) injection of oxytocin was followed by an enhancement of novelty-induced grooming in male and female rats. This effect was dose-dependent, in a dose range of 0.1-10 micrograms. Grooming activity of rats injected i.c.v. with 10 micrograms of oxytocin was 9-fold higher than that of saline-injected controls. The analysis of behavioral element composition revealed an increased occurrence of genital grooming in oxytocin-injected rats. A time-course study revealed a sustained increase in grooming activity of oxytocin-treated rats during 45 min of behavioral testing. Intraperitoneal (i.p.) injection of the dopamine antagonist, haloperidol, totally suppressed oxytocin-enhanced grooming. Furthermore, i.p. injection of the opiate receptor antagonist, naloxone, was followed by an attenuation but not a suppression of grooming enhanced by i.c.v. administration of oxytocin. In addition, a small but significant increase in grooming activity was observed after subcutaneous injection of oxytocin. These results suggest that oxytocin-enhanced grooming behavior involves central mechanisms, e.g. dopamine and opioid transmission in the brain.
Drago
F
F
Pedersen
C A
CA
Caldwell
J D
JD
Prange
A J
AJ
D000818:Animals; D005260:Female; D006120:Grooming / Q000187:drug effects*; D006220:Haloperidol / Q000008:administration & dosage / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D007279:Injections, Subcutaneous; D008297:Male; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology; D010121:Oxytocin / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012727:Sex Characteristics; D013997:Time Factors
D009270:Naloxone; D010121:Oxytocin; D006220:Haloperidol