Effects of electrical stimulation of ventral septal area on firing rates of pyrogen-treated thermosensitive neurons in preoptic anterior hypothalamus from rabbits.
Although there is considerable evidence supporting that fever evolved as a host defense response, it is important that the rise in body temperature would not be too high. Many endogenous cryogens or antipyretics that limit the rise in body temperature have been identified. Endogenous antipyretics attenuate fever by influencing the thermoregulatory neurons in the preoptic anterior hypothalamus (POAH) and in adjacent septal areas including ventral septal area (VSA). Our previous study showed that intracerebroventricular (I.C.V.) injection of interleukin-1beta (IL-1beta) affected electrophysiological activities of thermosensitive neurons in VSA regions, and electrical stimulation of POAH reversed the effect of IL-1beta. To further investigate the functional electrophysiological connection between POAH and VSA and its mechanisms in thermoregulation, the firing rates of thermosensitive neurons in POAH of forty-seven unit discharge were recorded by using extracellular microelectrode technique in New Zealand white rabbits. Our results show that the firing rates of the warm-sensitive neurons decreased significantly and those of the cold-sensitive neurons increased in POAH when the pyrogen (IL-1beta) was injected I.C.V. The effects of IL-1beta on firing rates in thermosensitive neurons of POAH were reversed by electrical stimulation of VSA. An arginine vasopressin (AVP) V1 antagonist abolished the regulatory effects of VSA on the firing rates in thermosensitive neurons of POAH evoked by IL-1beta. However, an AVP V2 antagonist had no effects. These data indicated that VSA regulates the activities of the thermosensitive neurons of POAH through AVP V1 but not AVP V2 receptor.
Dong
Jun
J
Department of Pathophysiology, Medical College of Jinan University, Guangzhou, Guangdong, China 510632 PR China. dongjunbox@163.com
Xie
Xin-Hua
XH
Lu
Da-Xiang
DX
Fu
Yong-Mei
YM
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology; D001833:Body Temperature Regulation / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D053583:Interleukin-1beta / Q000494:pharmacology / Q000502:physiology; D008297:Male; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology*; D011749:Pyrogens; D011817:Rabbits; D020665:Septum of Brain / Q000502:physiology*
D065092:Antidiuretic Hormone Receptor Antagonists; D053583:Interleukin-1beta; D011749:Pyrogens; D001127:Arginine Vasopressin; C025043:vasopressin, 1-(1-mercaptocyclohexaneacetic acid)-2-(O- methyl-L-tyrosine)-8-L-arginine-; C056186:argipressin, beta-mercapto-beta,beta-cyclopentamethylenepropionic acid(1)-Ile(2)-Abu(4)-