X. Chen et al., DIFFERENTIAL VENTRAL SEPTAL VASOPRESSIN RELEASE IS ASSOCIATED WITH SEXUAL DIMORPHISM IN PGE(2) FEVER, American journal of physiology. Regulatory, integrative and comparative physiology, 41(5), 1997, pp. 1664-1669
The vasopressinergic innervation of the ventral septal area (VSA) has
been shown to be implicated in antipyresis. Because this system is les
s well developed in female rats, we hypothesized that female rats woul
d display exaggerated febrile responses. We therefore examined the tem
perature responses of conscious and urethan-anesthetized rats of both
sexes to centrally administered prostaglandin E-2 (PGE(2)) and correla
ted these responses with the release and action of endogenous arginine
vasopressin (AVP) in the VSA. Both conscious [25 ng/5 mu l PGE(2) int
racerebroventricularly (icv)] and anesthetized (VSA microdialyzed, 50
ng/5 mu l PGE(2) icv) female rats had higher fevers than did males. In
fusion of an AVP V-1a receptor antagonist [1 nmol [d(CH2)(5)Tyr(Me)]AV
P] plus PGE(2) gave rise to higher fevers in males but not in females.
Measurements of AVP in microdialysates of the VSA showed that the rel
ease of endogenous AVP was increased in response to PGE(2) in males on
ly. Baseline AVP release in both sexes was similar. The results sugges
t that there is a sex-related difference in PGE(2) fever, which may be
accounted for by the differential AVP release in the VSA.