Since Enderby (1950) first described the use of pentamethonium for a temporary reduction of blood pressure in order to prevent excessive bleeding during surgical operations, only one report of the application of methonium compounds in orthopaedic surgery has appeared (Steven and Tovell 1954). A review of figures concerning blood loss and post-anaesthetic progress in 407 operations performed wit...

The purpose of this study was to identify changes in venomotor tone in the chronic low-dose angiotensin II (Ang II) model of hypertension and to establish the contribution of sympathetic nerve activation to these venomotor tone changes. Male Sprague-Dawley rats were acclimatized to a 0.4% or 2.0% NaCl diet for 7 days and then catheterized to allow chronic and repeated measures of arterial press...

We examined whether nitric oxide (NO) generated from neuronal NO synthase (nNOS) contributes to the reduced ability of the newborn to autoregulate retinal blood flow (RBF) and choroidal blood flow (ChBF) during acute rises in perfusion pressure. In newborn pigs (1-2 days old), RBF (measured by microsphere) is autoregulated over a narrow range of perfusion pressure, whereas ChBF is not autoregul...

Although evidence exists for exaggerated sympathetic nervous system activity in spontaneously hypertensive rats (SHR), there are no studies in conscious animals that directly demonstrate that this increased activity is functionally involved in the elevated vascular resistance of these animals. In our present study, 8-week-old and 13-week-old SHR and Wistar Kyoto controls (WKY) were chronically ...

The pressor responses to intravenous injections of angiotonin and s-methyl iso-thiourea have been studied in 50 hypertensive subjects and 20 normotensive controls. The rises of blood pressure in the two groups were similar, being but slightly greater in the hypertensives. After the blood pressure has been reduced with hexamethonium, however, the pressor responses to angiotonin, s-methyl iso-thi...

The maximum degree and time course of active reflex venoconstriction in chloralose-anesthetized dogs was studied. The mean circulatory filling pressure (Pmc) was measured by fibrillating the heart and rapidly pumping blood from the aorta to the vena cava until the systemic arterial pressure equaled the central venous pressure. Ventricular fibrillation was continued for 1 minute and was assumed ...

Hypotensive doses of hexamethonium were administered intravenously to 19 patients with various types of heart disease in congestive failure. Clinical improvement as judged by the usual methods was seen in most cases. Intracardiac or pulmonary artery pressures paralleled the fall of arterial pressures following hexamethonium in four patients with hypertensive heart disease in congestive failure....

Knowledge on murine blood pressure and heart rate control mechanisms is limited. With the use of a tethering system, mean arterial pressure (MAP) and pulse interval (PI) were continuously recorded for periods up to 3 wk in Swiss mice. The day-to-day variation of MAP and PI was stable from 5 days after surgery. Within each mouse (n = 9), MAP and PI varied by 21+/-6 mm Hg and 17+/-4 ms around the...

Renal denervation (RDNX) lowers mean arterial pressure (MAP) in patients with resistant hypertension. Less well studied is the effect of celiac ganglionectomy (CGX), a procedure which involves removal nerves innervating splanchnic vascular bed. We hypothesized that RDNX and CGX would both lower MAP genetically hypertensive Schlager (BPH/2J) mice through reduction sympathetic tone. Telemeters we...