Fig. 2

Relationships between cervical sympathetic nerves and the sympathoadrenal system in the regulation of cardiovascular parameters in the rat. a Typical examples of the effects of electrical stimulation of the peripheral cut end of the left AN (at black horizontal bars) before and after (5–30 min) sectioning of the left CST (at arrow) on the blood flow in the masseter muscle (MBF) on both sides, lower lip (LBF) on the left side, vascular conductance (VC) of the measurement sites and systemic arterial blood pressure (SABP) during high spontaneous activity in the CST. Increases in the VC were assessed by measuring the height of peak (†) during the response. b Typical examples of the effects of the left AN stimulation before and after sectioning of the left CST on the left MBF and VC in the masseter muscle during low spontaneous activity in the CST. Electrical stimulation of the AN was delivered for 20 s with a supramaximal voltage (10 V) at 20 Hz using 2-ms pulses. Changes in blood flows (a.u. arbitrary units) and VC (a.u./mmHg) in the masseter muscle and lower lip and SABP were measured simultaneously. c Plot of changes in the VC evoked by AN stimulation vs. changes in the baseline VC after CST sectioning (*) in the masseter muscle. The white traces in a and b indicate the mean VC at the measuring sites