The rate of dopa synthesis in the rat superior cervical ganglion was increased 4- to 6-fold during continuous electrical stimulation of the cervical sympathetic trunk at 10 Hz for 30 min. This increase was only partially blocked by 3 mM hexamethonium and was not significantly affected by 6 microM atropine. In the presence of both hexamethonium and atropine, nerve stimulation still produced a 2-...

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 ...

Although the importance of the vagal nerve in the pathogenesis of bronchial asthma has been reported, its precise contribution is still not fully understood. To shed more light on this area, we evaluated the possible contribution of vagal reflex in histamine-induced bronchoconstriction (HIB), and decided the site of action of histamine on the vagal nerve. For this purpose, we studied the effect...

The response of atrial pressure, venous pressure, pulse and respiratory rates to intravenous hexamethonium in 38 selected patients was studied. The drug seemed more effective where vascular tone was greater. Increased venous tone was indicated in congestive heart failure. The possible useful role of intravenous hexamethonium as an adjunct in the treatment of congestive heart failure was conclud...

During the course of treating 54 severely hypertensive patients with parenteral hexamethonium bromide, wehave observed the development of unexpected pulmonary dyspnea and associated radiographic changes in the lungs in three cases after 7, 9, and 12 months' therapy respectively. Two of these came to autopsy; the third has recovered. The object of this paper is to record the clinical, radiologic...

In 13 patients with grade III or grade IV hypertensive retinopathy the effect of intramuscular hexamethonium bromide on cerebral circulation and metabolism has been studied. The results have been compared with Dewar's study of hexamethonium in less severe hypertensive patients and with Kety's results following differential spinal sympathetic block. Sixty minutes after in-tramuscular hexamethoni...

Our objective was to determine whether atrial fibrillation (AF) results from excessive activation of intrinsic cardiac neurons (ICNs) and, if so, whether select subpopulations of neurons therein represent therapeutic targets for suppression of this arrhythmogenic potential. Trains of five electrical stimuli (0.3-1.2 mA, 1 ms) were delivered during the atrial refractory period to mediastinal ner...

This study represents an effort to distinguish between neurogenic and humoral vasoconstrictive factors in a representative group of hypertensive patients by the response to hexamethonium ganglionic blockade. The correlation between intravenous hexamethonium sensitivity and subsequent treatment response was also determined. O~NE of the most difficult problems in essential hypertension is to sele...

Neurogenic (autonomic) factors in hypertensive vascular disease (1, 2) may be studied with hexamethonium 2 which reduces arterial blood pressure by blockade of the sympathetic ganglia. When the blood pressure is reduced acutely in this manner, alterations in renal hemodynamics have been observed. Following a single dose of hexamethonium administered parenterally to patients with hypertension, t...