Inhibitory effects of angiotensin II on barosensitive rostral ventrolateral medulla neurons of the rat

Clinical and Experimental Pharmacology & Physiology
D Bertram, J H Coote

Abstract

1. The brain renin-angiotensin system can influence arterial baroreceptor reflex control of blood pressure (BP) through both direct and indirect effects on sympathetic premotor neurons of the rostral ventrolateral medulla (RVLM). The present study examined the direct effect of angiotensin (Ang) II applied by microiontophoresis on the ongoing activity of single RVLM neurons. 2. In 26 urethane-anaesthetized Wistar rats, recordings of single unit activities of barosensitive RVLM neurons were made from one barrel of a six-barrel micropipette assembly. The other five barrels were filled with either L-glutamate, AngII, valsartan (an AT1 receptor antagonist), PD 123177 (an AT2 receptor antagonist) and saline. All drugs were applied by microiontophoresis. 3. Mean BP was 83 +/- 3 mmHg. Application of AngII inhibited the ongoing activity of RVLM neurons, identified as barosensitive because their activity was inhibited by a phenylephrine- induced increase in BP, from 12.6 +/- 1.5 to 5.4 +/- 1.1 Hz (n=24; P < 0.001). Angiotensin II also inhibited the glutamate-evoked excitation of barosensitive RVLM neurons from 15 +/- 3 to 5.8 +/- 2.0 Hz (n=6; P < 0.001). Valsartan significantly increased neuronal activity from 9.5 +/- 2.3 to 13.5 +/- 3.2...Continue Reading

References

Dec 1, 1980·Journal of Neuroscience Methods·G PaxinosP C Emson
Feb 1, 1994·Psychological Reports·H P ParetteT E Smith
Jun 1, 2000·Brazilian Journal of Medical and Biological Research = Revista Brasileira De Pesquisas Médicas E Biológicas·T TagawaR A Dampney
Nov 22, 2000·American Journal of Physiology. Heart and Circulatory Physiology·S Ito, A F Sved

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Citations

Dec 17, 2010·Current Opinion in Pharmacology·Lie Gao, Irving H Zucker
Mar 26, 2003·Hypertension·Dmitry N Mayorov, Geoffrey A Head
Oct 8, 2005·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Mohammed J SheriffRoger A L Dampney
Feb 14, 2014·American Journal of Physiology. Regulatory, Integrative and Comparative Physiology·Takeshi Saigusa, Jun Arita

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