期刊
BRAIN RESEARCH
卷 1448, 期 -, 页码 101-110出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.brainres.2012.02.021
关键词
Brain renin-angiotensin system; Sympathetic tone; Paraventricular nucleus; Transgenic rat
资金
- INCT Nanobiofar
- Conselho Nacional de Desenvolvimento Cientifico e Tecnologico do Brasil (CNPq)
- Fundacao de Amparo a Pesquisa de Minas Gerais (FAPEMIG)
- CAPES/DAAD (PROBRAL)
Previous evidence indicates that a balance between inhibitory gabaergic and excitatory angiotensinergic factors in the PVN is important for cardiovascular control. We investigated the cardiovascular response evoked from activation or blockade of GABA(A) receptors in the paraventricular nucleus (PVN), in transgenic rats with low brain angiotensinogen [TGR(ASrAOGEN)]. Brain Ang II and Ang-(1-7) levels were also determined. In functional experiments, TGR(ASrAOGEN) and Sprague Dawley rats (SD, control) were anesthetized with urethane and blood pressure (BP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded. Brain Ang II and Ang-(1-7) levels were largely reduced in TGR(ASrAOGEN) compared with SD rats. Inhibition of PVN neurons with the GABAA agonist, muscimol (1 nmol/100 nL), resulted in an attenuated fall in all cardiovascular variables in TGR(ASrAOGEN) compared with SD rats. This difference was particularly pronounced in HR (TGR Mus -23 +/- 6 bpm vs. -77 +/- 9 bpm SD Mus; P<0.05) and RSNA (TGR -3 +/- 10% vs. -29 +/- 8% SD; P<0.05). Furthermore, the sympathetic response evoked by blockade of GABA(A) receptors in the PVN of TGR(ASrAOGEN) was also largely suppressed. The present data indicate that the sympathetic outflow mediated by PVN neurons under basal conditions is suppressed in TGR(ASrAOGEN) rats corroborating the functional significance of brain angiotensin production in the central regulation of sympathetic output to the cardiovascular system. (C) 2012 Elsevier B.V. All rights reserved.
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