Fig. 3

Effects of cardiovascular excitation induced by CeA microstimulation on the baroreceptor bradycardia response. a, b Representative recordings of AP (a) and HR (b) responses to chemical activation to assess baroreceptor reflex gain (left column) and following CeA microstimulation (stimulation onset indicated by black arrow and duration by bar length in each figure, 200 μA, 50 Hz and 30 s; right column). The baroreceptor reflex was induced by i.v. injection of phenylephrine (15 μg/kg). c Average baroreceptor reflex gain calculated as peak HR divided by peak MAP in each rat (n = 5). There was no significant effect of CeA microstimulation on baroreceptor reflex gain (p > 0.05), suggesting a shift in the AP set point, known as the ‘resetting’ process. Statistical significance was tested using Student’s paired t test