The Somatosympathetic Reflex in Rats with Different Models of Arterial Hypertension

The aim of the present work was to perform a comparative study of the magnitudes of spontaneous and evoked (by single afferent stimuli) activity in a sympathetic nerve in animals with arterial hypertension of different causes. Acute experiments on anesthetized Wistar rats with renovascular hypertension and rats of the spontaneously hypertensive strain SHR were performed to record spontaneous and evoked (somatosympathetic reflex) activity in the cervical sympathetic trunk. Tonic electrical activity in the sympathetic nerve in hypertensive rats was greater than that in normotensive individuals. The magnitudes of the somatosympathetic reflex in rats with models of arterial hypertension differed from that of the reflex in control animals. The magnitude of the reflex was decreased in rats with the renovascular model of hypertension, while the reflex was increased in rats with spontaneous hypertension, as compared with normotensive animals. The time characteristics of the reflex in hypertensive rats also showed differences. It is suggested that different components of the brainstem show different changes in their functional activity in rats with different experimental models of hypertension.