Barrel rotation induced by central arginine8-vasopressin treatment: involvement of neurohypophyseal peptide receptors.
Two series of experiments were done to investigate the mechanism underlying arginine8-vasopressin (AVP)-induced barrel rotation in rats. In the first series, the effect of intracerebroventricular (ICV) administration of various neurohypophyseal hormone antagonists on AVP-induced barrel rotation was studied. The more vasopressin was given, the more the rats exhibited barrel rotation. ICV pretreatment with a V1 vasopressin receptor antagonist, d(CH2)5[Tyr(Me)2]AVP, prevented barrel rotation, while similar treatment with a V2-antagonist, d(CH2)5[dIle2Ile4]AVP, did not affect vasopressin-induced barrel rotation. However, Des-Gly,NH2d(CH2)5[Tyr)Me2)Thr4Orn8]-vasotocin, a specific oxytocin antagonist, potentiated the effect of AVP on barrel rotation. The second experiment was performed in rats equipped with a telemetry system to measure heart rate (HR), core temperature (CT), and gross locomotor activity. Also, in this experiment the incidence of AVP-induced barrel rotation was dose-dependent, as was the number of rats that died. Barrel rotation was accompanied by a significant decrease in CT and HR, while rats that did not develop hypothermia did not show barrel rotation. These results suggest that a V1 receptor is involved in barrel rotation. Since AVP-induced hypothermia is also mediated by a V1 receptor, it is postulated that hypothermia is a prerequisite for barrel rotation to occur. Further experiments are needed to substantiate this hypothesis.
Diamant
M
M
Rudolf Magnus Institute, Utrecht University, The Netherlands.
Baars
A M
AM
Kovács
G L
GL
De Wied
D
D
D000818:Animals; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000494:pharmacology*; D001831:Body Temperature / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009479:Neuropeptides / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011979:Receptors, Pituitary Hormone / Q000187:drug effects*; D013239:Stereotyped Behavior / Q000187:drug effects*
D009479:Neuropeptides; D011979:Receptors, Pituitary Hormone; D001127:Arginine Vasopressin