Pressor responses to central hypertonic NaCl stimulation in conscious turkeys.
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.
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000502:physiology*; D003243:Consciousness; D007276:Injections, Intraventricular; D008297:Male; D012084:Renin-Angiotensin System; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013565:Sympatholytics / Q000494:pharmacology; D014422:Turkeys / Q000502:physiology*
D012462:Saline Solution, Hypertonic; D013565:Sympatholytics; D012965:Sodium Chloride