At 10% blood volume expansion, spontaneously hypertensive rats showed a significantly greater reflex inhibition of splanchnic nerve sympathetic activity (43%) compared to normotensive rats (33%).
Absolute Event Rate: 43% vs 33%
The reflex inhibition of the sympathetic activity in the splanchnic nerves was recorded upon volume expansion with blood in awake spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto rats (WKR) at an age of 16-20 weeks. At 10% blood volume expansion SHR showed a significantly greater nerve inhibition (43%) in comparison with WKR (33%). This augmented reflex response was not caused by the arterial baroreceptors, because the sensitivity of the arterial baroreceptor reflex arch, if anything, tended to be lower in SHR and the increase in arterial blood pressure upon volume load was also lower in SHR. It is suggested that the reason for this increased reflex inhibition in SHR is an augmented low pressure receptor response. The mechanism behind this is discussed. The most likely explanation is a decreased distensibility of the venous system, the systemic and/or the pulmonary veins.
Ricksten et al. (Mon,) conducted a other in Hypertension. Volume expansion with blood vs. Normotensive Wistar-Kyoto rats (WKR) was evaluated on Reflex inhibition of the sympathetic activity in the splanchnic nerves. At 10% blood volume expansion, spontaneously hypertensive rats showed a significantly greater reflex inhibition of splanchnic nerve sympathetic activity (43%) compared to normotensive rats (33%).