veratrine and Hypertension

Intense activation of the sympathetic nervous system (SNS) decreases the contractile state of the rabbit left ventricle (LV). In this study, we determined the time course of LV dysfunction after massive central activation of the SNS in dogs. Veratrine (40-80 micrograms/kg) was injected intracisternally to activate the SNS in six chloralose-anesthetized dogs, and LV end-diastolic pressure (LVEDP), cardiac output, heart rate, and aortic pressure (Pa) were measured at 30-min intervals for 3 h. Pa increased from 147 +/- 8 (SE) to 272 +/- 7 mmHg (1 mmHg = 133.3 Pa) within 15 min, then declined to 148 +/- 16 mmHg by 1 h LV function curves (stroke work versus LVEDP or stroke work verus LV transmural pressure) showed a marked decrease in slope and a shift to the right within minutes after activating the SNS, which persisted for the duration of the experiment. These data indicate that LV contractility was diminished in these animals. No changes in LV function were observed in three dogs serving as time-matched controls. In three additional dogs, LV pressure was raised to a degree similar to that observed after SNS activation by constricting the ascending aorta for 1 h. These animals exhibited only modest shifts in the LV function curve during and after aortic constriction. Mean plasma catecholamine concentration increased by one to two orders of magnitude in animals after SNS activation, but only minor changes were observed in the other two groups. We conclude that myocardial contractility declines markedly soon after massive SNS activation and is not solely a function of the initial hypertensive period.

Topics: Acidosis; Anesthesia; Animals; Blood Pressure; Cardiac Output; Catecholamines; Dogs; Female; Heart Rate; Heart Ventricles; Hypertension; Male; Microscopy, Electron; Sympathetic Nervous System; Ventricular Function, Left; Veratrine

Exposure to vanadate was found to induce arterial hypertension through effects on renin-angiotensin-aldosterone, renal peptidergic, and central and peripheral catecholaminergic systems. Vanadate increased, mainly in vascular myocells, both receptor-operated Ca2+ channel- and cyclic-AMP-dependent availability of Ca2+ for contractile processes. Vanadate was selectively accumulated by tissues in the +4 oxidation state (vanadyl).

Topics: Aldosterone; Animals; Blood Pressure; Bradykinin; Bucladesine; Catecholamines; Diastole; Enkephalins; Heart Rate; Hypertension; Hypothalamus; Isoproterenol; Kallikreins; Lysine Carboxypeptidase; Male; Myocardium; Neprilysin; Peptidyl-Dipeptidase A; Rats; Rats, Sprague-Dawley; Renin; Systole; Time Factors; Vagotomy; Vanadates; Veratrine

Topics: Antihypertensive Agents; Blood Pressure; Bretylium Compounds; Diuretics; Evaluation Studies as Topic; Ganglionic Blockers; Guanethidine; Humans; Hydralazine; Hypertension; Hypnotics and Sedatives; Methyldopa; Propranolol; Reserpine; Veratrine

Topics: Alkaloids; Animals; Blood Pressure; Cerebral Ventricles; Diphenhydramine; Histamine; Histamine Release; Hypertension; Morphine; Perfusion; Rabbits; Respiration; Spectrophotometry; Tubocurarine; Veratrine

Topics: Hypertension; Veratrine; Veratrum Alkaloids

Topics: Blood Pressure; Exercise; Exercise Tolerance; Hemodynamics; Humans; Hypertension; Protoveratrines; Veratrine

Topics: Biological Phenomena; Blood Circulation; Blood Pressure; Blood Pressure Determination; Hypertension; Physiological Phenomena; Protoveratrines; Veratrine

Topics: Biological Assay; Blood Pressure; Blood Pressure Determination; Essential Hypertension; Hypertension; Veratrine; Veratrum

Topics: Biomedical Research; Blood Pressure; Blood Pressure Determination; Hypertension; Protoveratrines; Veratridine; Veratrine; Veratrum Alkaloids