Pharmacological modulation of the cardiovascular response to hypertonic NaCl injection in the anteroventral area of the rat brain third ventricle.
The anteroventral area of the rat brain third ventricle (AV3V) was stimulated by stereotaxically placed microinjections (1 microliter) of hypertonic 1.5 mol/l NaCl and the responses of mean arterial pressure (MAP) and heart rate (HR) were recorded. Previous injection of terazosin or propranolol (5.0 micrograms) into AV3V, 15 min before 1.5 mol/l NaCl microinjection, did not alter the cardiovascular response pattern induced by 1.5 mol/l NaCl. Prior AV3V treatment with ketanserin (1.0 microgram) significantly reduced (p < 0.01) the MAP and HR increase induced by 1.0 microliter of 1.5 mol/l NaCl without changing basal cardiovascular parameters. Prior AV3V treatment with losartan (10.0 micrograms) significantly reduced (p < 0.01) the hypertension and tachycardia induced by hypertonic NaCl administration. Thus, AV3V serotonin and angiotensin II-sensitive neurons may exert an excitatory role on blood pressure and HR involved with the sympathetic discharge produced by hypertonic NaCl stimulation.
Rosa
F
F
Department of Pharmacology, J.M. Vargas School of Medicine, San José, Caracas, Venezuela.
Vásquez
J
J
Lupi
J
J
Lezama
E
E
Romero-Vecchione
E
E
D000803:Angiotensin I / Q000378:metabolism; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism; D011945:Receptors, Angiotensin / Q000187:drug effects; D011985:Receptors, Serotonin / Q000187:drug effects; D012462:Saline Solution, Hypertonic; D013238:Stereotaxic Techniques; D014667:Vasopressins / Q000037:antagonists & inhibitors
D057911:Angiotensin Receptor Antagonists; D018340:Receptors, Adrenergic, alpha-1; D011943:Receptors, Adrenergic, beta; D011945:Receptors, Angiotensin; D011985:Receptors, Serotonin; D012462:Saline Solution, Hypertonic; D014667:Vasopressins; D000803:Angiotensin I