Central vasopressin in the modulation of catecholamine release in conscious rats
作者:
Kathryn A. King,
Gordon Mackie,
Catherine C. Y. Pang,
Richard A. Wall,
期刊:
Canadian Journal of Physiology and Pharmacology
(NRC Available online 1985)
卷期:
Volume 63,
issue 12
页码: 1501-1505
ISSN:0008-4212
年代: 1985
DOI:10.1139/y85-247
出版商: NRC Research Press
数据来源: NRC
摘要:
Neurons containing arginine vasopressin (AVP) have been shown to project from the paraventricular nucleus of the hypothalamus to the nucleus tractus solitarius (NTS) in the medulla. We investigated whether AVP acts in brain stem regions to influence sympathoadrenal outflow. Cannulae were implanted into the fourth ventricle of rats 7 days prior to the experiment. The effects of intracerebroventricular (icv) injections of AVP, the vehicle, and AVP antagonist,d(CH2)5Tyr(Me)AVP, on mean arterial pressure (MAP) and plasma noradrenaline (NA) and adrenaline (A) levels were determined in conscious unrestrained rats. Injections of AVP (icv, 23 and 73 ng/kg) but not the vehicle increased MAP and plasma NA and A levels. In contrast, iv injection of AVP increased MAP but decreased plasma concentrations of A and NA. The pressor response to icv injection of AVP was abolished by prior icv injection of AVP antagonist. Injection of AVP antagonist (icv, 0.5 and 1.5 μg/kg) had no effect on MAP or plasma NA or A levels. These results show that centrally injected AVP activates sympathoadrenal outflow, possibly via an inhibition of baroreceptor reflexes. Since centrally administered AVP antagonist did not influence MAP or plasma NA or A levels, it appears that endogenously released AVP does not have a tonic influence on central cardiovascular reflex system in conscious, unrestrained rats.
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