Control of cardiac chronotropy by the Nucleus Ambiguus and Dorsal Motor Nucleus of the Vagus: A light hand on the cardiac tiller

Abstract

Neurons of the Nucleus Ambiguus (NA) and Dorsal Motor Nucleus of the Vagus (DMV) were transduced with a lentiviral vector with PRS promotor driving channelrhodopsin2 expression. Wistar rats (P21) received vector injections to the NA, DMV or both and were later used in working heart‐brainstem preparations. Opto‐activation of either NA or DMV neurons produced bradycardias that were titratable and temporally locked to the stimulus. Vigorous responses were evoked by opto‐activation of NA (21–109 bpm; mean 49±11, n=8), compared to modest DMV responses (0–13 bpm; mean 6±2, n=7). Rats with both NA and DMV transduced showed a similar pattern: strong NA and small non‐significant DMV responses. Thorac..