Left and bilateral aortic depressor nerve stimulation mediated significantly greater reflex reductions in mean arterial pressure compared to right-sided stimulation in both male and female rats.
This study demonstrates that laterality and sexual dimorphism significantly influence the central integration of baroreceptor afferent inputs in rats, with left-sided and bilateral stimulation evoking stronger depressor responses than right-sided stimulation.
p-value: p=<0.001
= 18) were instrumented for left, right and bilateral aortic depressor nerve (ADN) stimulation (1-40 Hz, 0.2 ms, 0.4 mA for 20 s) and measurement of mean arterial pressure (MAP), heart rate (HR) and mesenteric (MVR) and femoral (FVR) vascular resistance. Female rats were matched for the diestrus phase of the estrus cycle. Left, right and bilateral ADN stimulation evoked frequency-dependent drops in MAP, HR, and MVR, and increases in FVR. Irrespective of sex, left and bilateral ADN stimulation as compared to right-sided stimulation mediated greater reflex reductions in MAP, HR, and MVR but not in FVR. In males, reflex bradycardic responses were greater in response to bilateral stimulation relative to both left- and right-sided stimulation. In females, left ADN stimulation evoked the largest increase in FVR. Left and bilateral ADN stimulations evoked greater reductions in MAP and MVR while left-sided stimulation produced larger increases in FVR in females compared with males. All other reflex responses to ADN stimulation were relatively comparable between males and females. These results show a differential baroreflex processing of afferent neurotransmission promoted by left versus right baroreceptor afferent inputs and sexual dimorphism in the expression of baroreflex responses in rats of either sex. Collectively, these data add to our understanding of physiological mechanisms pertaining to baroreflex control in both males and females.
Salman et al. (2020) studied Healthy (Normotensive Sprague Dawley rats) (n=18). Left and bilateral aortic depressor nerve (ADN) stimulation vs. Right ADN stimulation was evaluated on Reflex reductions in mean arterial pressure (MAP) (p=<0.001). Left and bilateral aortic depressor nerve stimulation mediated significantly greater reflex reductions in mean arterial pressure compared to right-sided stimulation in both male and female rats.