veratrine and Aortic-Valve-Stenosis

The present study was undertaken to determine whether intracoronary (left circumflex) veratrine (ICV) infusions and increases in left ventricular (LV) systolic pressure influence renal circulatory and excretory function in chronically instrumented conscious dogs (n = 19). Thirty minutes of ICV infusions decreased arterial pressure by 15-20 mmHg, but heart rate, urine flow, sodium excretion, and free water clearance did not change. Intravenous nitroprusside infusions, which also lowered arterial pressure by 15-20 mmHg, increased heart rate while urine flow, sodium excretion, and free water clearance were significantly decreased. Heart rate and renal excretory function also did not change during a 15- to 20-mmHg decrease in arterial pressure when LV systolic pressure was simultaneously raised to approximately 170 mmHg by ascending aortic occlusion. The topical application of a local anesthetic in the region of the left main coronary artery abolished the Bezold-Jarisch reflex and the attenuation of hypotension-induced salt and water retention and tachycardia by ICV. Renal plasma flow and glomerular filtration rate were not altered during any of the above experimental treatments. These results suggest that in the conscious dog chemical and mechanical stimulation of LV sensory receptors with afferents in the pericoronary region can modulate the neurohumoral reflex control of renal excretory function independent of local filtration effects.

Topics: Animals; Aortic Valve Stenosis; Blood Pressure; Cardiac Catheterization; Consciousness; Dogs; Heart Rate; Hypotension; Kidney; Male; Nitroprusside; Renal Circulation; Time Factors; Urination; Veratrine