Fig. 7.

P2 receptors in NTS neurons mediating sympathetic withdrawal and adrenaline release in response to HDA stimulation. a Representative recording of one animal in response to stimulation of the hypothalamic defense area (HDA; 150–200 μA, 0.6 ms, 100 Hz for 5 s) before and after intravenous infusion of phentolamine (1 mg/kg), and after following microinjections of suramin (10 mM) into the nucleus tractus solitarii (NTS). AP arterial blood pressure; HR heart rate; HVC hindlimb vascular conductance. b Grouped data of increases elicited in mean arterial pressure (MAP) and HR by hypothalamic stimulation before and after intravenous infusion of phentolamine, and after following microinjections of suram ininto the NTS. c Maximum responses in HVC generated by hypothalamic stimulation after intravenous infusion of phentolamine, and after following microinjections of suramin into the NTS. n.s. non-significant; *P < 0.05 to control; **P < 0.01 to control; +P < 0.05 to phenolamine