[Comparative study of baroreceptor reflexes in cats and rats]

The sensitivity of baroreceptor reflexes, the intensity of heart rate changes, and the electrical activity of renal nerve were compared in acute and chronic experiments with changing activity of arterial baroreceptor afferents in rats and cats. Activation of the baroreceptor afferents was due to blood pressure elevations induced with phenylephrine, deceleration of electrical activity of renal nerve was induced by baroreceptor deafferentation. The sensitivity of baroreceptor reflexes, the absolute and relative acceleration of heart rate after baroreceptor deafferentation, as well as the intensity of renal nerve activity suppression were considerably higher in cats as compared with rats.