Angiotensin and Peripheral Sympathetic Nerve Activity

Abstract

On the isolated vas deferens of the guinea-pig angiotensin potentiated strongly the height of contractions due to electrical stimulation of the hypogastric nerve; it did not affect the responses to noradrenaline and acetylcholine, nor did it elicit any contraction when given alone. Angiotensin likewise potentiated the responses ofthe cat spleen to nerve stimulation, but it also induced by itself strong contractions of the organ and reduction of the venous outflow. In experiments on the arterial blood pressure of anaesthetized and spinal cats, in which sympathetic postganglionic transmission was temporarily blocked by nicotine or tetramethylammonium, pressor responses to angiotensin were strongly reduced. As with some ganglion-stimulating drugs, the pressor responses, enhanced after a second series of nicotine injections, were reduced to the control level by hexamethonium. These findings indicate the involvement of peripheral sympathetic nerves in the action of angiotensin: the hypothesis is advanced that angiotensin acts at the peripheral nerve endings by promoting a greater output of noradrenaline.

Central components of the renin‐angiotensin system

“…More recently various authors have described nervously mediated effects of angiotensin II either peripherally (McCubbin & Page, 1963;Feldberg & Lewis, 1964;Benelli, Della Bella & Gandini, 1964;Laverty, 1963;Distler, Liebau & Wolff, 1965;Lewis & Reit, 1965;Aiken & Reit, 1968) or via a central mechanism (Buckley, Bickerton, Halliday & Kato, 1963;Ferrario, Dickinson, Gildenberg & McCubbin, 1969;Scroop & Lowe, 1968;Scroop & Whelan, 1966).…”

The interaction between angiotensin and sympathetic vasoconstriction in the isolated artery of the rabbit ear

“…tissues to noradrenaline released from peripheral sympathetic nerves both in whole animals (McCubbin & Page, 1963a, b;Zimmerman & Gomez, 1965) and in isolated tissues (Benelli et al, 1964;Thoenen et al, 1965;Hertting & Suko, 1966). Finally, in some vascular beds the vasoconstrictor action of angiotensin is dependent on an intact sympathetic innervation and is greatly reduced by procedures abolishing sympathetic tone (Zimmerman, 1962;Laverty, 1963;Benelli et al, 1964).…”

“…Finally, in some vascular beds the vasoconstrictor action of angiotensin is dependent on an intact sympathetic innervation and is greatly reduced by procedures abolishing sympathetic tone (Zimmerman, 1962;Laverty, 1963;Benelli et al, 1964).…”

“…McCubbin & Page (1963a, b) found that the pressor responses in anaesthetized dogs to procedures which caused a release of noradrenaline were enhanced during infusions of angiotensin. Benelli, Della Bella & Gandini (1964) found that administration of angiotensin specifically increased the response of the guinea-pig isolated vas deferens to sympathetic stimulation and that the pressor response to angiotensin in cats was decreased by blocking sympathetic ganglia with tetramethyl ammonium or nicotine. They concluded that angiotensin potentiates sympathetic stimulation by promoting a greater output of noradrenaline and that the vasoconstrictor response to an injection of angiotensin is partly due to the liberation of noradrenaline.…”

“…The purpose of the present investigation was to test the hypothesis of Benelli et al (1964) that angiotensin has both direct vasoconstrictor activity and an indirect action involving an increased release of noradrenaline from sympathetic nerveendings. We have used the isolated central artery of the rabbit ear preparation described by De la Lande & Rand (1965) because it affords a convenient method of studying the interaction between angiotensin and vasomotor sympathetic nerves in a simplified in vitro system.…”