AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 2 258-R263, Copyright © 1986 by American Physiological Society
Pressor responses to central hypertonic NaCl stimulation in conscious turkeys
J. C. Lee, D. M. Denbow, M. D. Ashen and A. D. Roudabush
The purpose of this investigation was to examine the possible involvement
of the central renin-angiotensin system in the pressor response to the
intracerebroventricular (icv) injection of hypertonic NaCl in conscious
turkeys. The icv injection was accomplished via a stereotaxically implanted
stainless steel guide cannula in the lateral cerebral ventricle. The
arterial blood pressure (AP) of the turkey was measured by means of a PE
catheter in the left brachial artery. The icv administration of hypertonic
NaCl caused a dose-dependent increase of AP. The mean AP increases due to
10-microliter icv injections of 0.9, 3.6, and 7.2% NaCl were 1.4 +/- 1.4,
18.1 +/- 3.0, and 31.2 +/- 3.2 (SE) mmHg, respectively. These changes were
statistically significant (P less than 0.001). The icv administration of
captopril, [Sar1, Ile8]angiotensin II, or pentobarbital sodium markedly
reduced the pressor response to the icv injection of hypertonic 7.2% NaCl.
Blockade of central adrenergic receptors with phentolamine and propranolol
was without effect. These results support the contention that the central
renin-angiotensin system may directly contribute to pressor responses
induced by central hypertonic NaCl stimulation.
