[Role of nitric oxide in inhibitory effect of somatic afferent inputs on central pressor response].
To investigate the role of nitric oxide in the inhibitory effect of somatic afferent input on the pressor response caused by electrical stimulation of the paraventricular nucleus of the hypothalamus (PVN).



SD rats anesthetized by urethane were used in the study. Bipolar stainless stimulating electrode was inserted into PVN for electrical stimulation. Multi-barreled micropipettes were used for microinjection of L-NAME or normal saline into the lateral ventricle or amygdala. Deep peroneal nerve (DPN) was stimulated with electrical current pulses of 0.4 mA with duration of 0.5 ms at 4 Hz for 5 min. PVN was stimulated by electrical current pulses of 0.3 mA with duration of 0.5 ms at 80 Hz for 10 sec.



Electrical stimulation of PVN increased mean arterial pressure. Stimulation of DPN significantly inhibited the pressor response induced by stimulation of PVN (P<0.01), with the inhibitory percentage of 43.27%. Microinjection of L-NAME (0.5 mol/L,10 microl) into the lateral ventricle of brain attenuated the inhibitory effect of DPN. The inhibitory percentage decreased from 47.73% to 12.49% (P<0.05). Microinjection of L-NAME (2 mol/L,100 nl) into amygdala reduced the inhibitory effect of DPN. The inhibitory percentage of stimulating DPN on the pressor response decreased from 50.71% to 25.30% (P<0.05).



Nitric oxide in the brain and amygdala are involved in the inhibitory effect of somatic afferent input on central pressor response.
Shen
Yi-hong
YH
The Department of Physiology, College of Medicine, Zhejiang University, Hangzhou, 310058, China.
Cai
Yong
Y
Lan
Qian-qian
QQ
Gao
Xuan
X
Xia
Qiang
Q
Yu
Yand-qin
YQ
D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology; D000679:Amygdala / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D010543:Peroneal Nerve / Q000502:physiology; D011311:Pressoreceptors / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester