SUMMARY1. Afferent splanchnic nerve stimulation with different frequencies in Wistar Kyoto rats caused depressor and pressor responses depending on the frequency employed.2. Similar visceral afferent activation in spontaneously hypertensive rats caused depressor responses at all frequencies of stimulation.3. It is suggested that the central integrated mechanisms for activating a cardiovascular state change as evoked by visceral afferents may differ in the established hypertensive rat from that of the normotensive.