[Role of oxotremorine in arginine vasopressin-induced hypothermia and its effects on behavioral thermoregulatory response in rats].
OBJECTIVE
To investigate the role of oxotremorine in arginine vasopressin (AVP)-induced hypothermia and its effects on the behavioral thermoregulatory response.


METHODS
Core temperature (Tc), brown adipose tissue (BAT) temperature and motor activities were monitored in undisturbed female SD rats using radiotelemetry. The behavioral thermoregulatory response was monitored in rats using radiotelemetric temperature gradient apparatus. Effect of AVP (10 microg/kg) and oxotremorine (0.25 mg/kg) on Tc, motor activities, BAT temperature (T(BAT)), grooming activities and the behavioral thermoregulatory response were observed in rats.


RESULTS
Administration of AVP and oxotremorine caused a significant drop in Tc, T(BAT), and an increases in grooming activities, respectively. The hypothermic responses were accompanied with a preference for cooler ambient temperature. Oxotremorine augmented the reduction of Tc, T(BAT), and the elevation of grooming activities resulting from AVP, and lasting a longer time. Administration of oxotremorine followed immediately by AVP injection in rats was also shown to induce a preference for cooler ambient temperature, but there was no significant difference compared with AVP.


CONCLUSIONS
AVP-induced hypothermia was related with the set point temperature reduction, inhibiton of BAT thermogenesis and an increases in grooming activities. Oxotremorine could participate in peripheral AVP-induced hypothermia by affecting BAT thermogenesis and behavioral thermoregulation.
Department of Physiology, Thermoregulatory Laboratory, Chengdu Medical College, Chengdu 610083, China.
Zi-Ling
ZL
Shen
Yong-Lu
YL
Yang
Bing
B
Sun
Yu
Y
Tang
Nian
N
Wang
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001522:Behavior, Animal; D001833:Body Temperature Regulation; D005260:Female; D007036:Hypothermia, Induced; D010095:Oxotremorine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001127:Arginine Vasopressin; D010095:Oxotremorine