Fig. 2. Cardiovascular changes upon electrical stimulation of the right (open bars) or the left (closed bars) vagus in the rattlesnake (Crotalus durissus). Data are presented as the relative changes in heart rate (f_H), systemic blood pressure (P_sys), systemic stroke volume (V_s,_sys) and stroke flow in the pulmonary artery (V_s,pul), caused by peripheral electrical simulation of the left or right vagus at intensities causing approximately 20 or 60% reductions in f_H, respectively. Data are presented as means ± s.e.m (N=9). Values that are significantly different from the resting undisturbed condition are marked with an asterisk.