Role of pressor mechanisms from the NTS and CVLM in control of arterial pressure

Role of pressor mechanisms from the NTS and CVLM in control of arterial pressure

Autor Moreira, Thiago Santos Autor UNIFESP Google Scholar
Sato, Monica Akemi Google Scholar
Takakura, Ana Carolina Thomaz Autor UNIFESP Google Scholar
Menani, Jose Vanderlei Google Scholar
Colombari, Eduardo Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
UNESP
Universidade Federal do ABC (UFABC)
Resumo In the present study, we investigated the effects of inhibition of the caudal ventrolateral medulla (CVLM) with the GABA(A) agonist muscimol combined with the blockade of glutamatergic mechanism in the nucleus of the solitary tract (NTS) with kynurenic acid (kyn) on mean arterial pressure (MAP), heart rate (HR), and regional vascular resistances. in male Holtzman rats anesthetized intravenously with urethane/chloralose, bilateral injections of muscimol (120 pmol) into the CVLM or bilateral injections of kyn (2.7 nmol) into the NTS alone increased MAP to 186 +/- 11 and to 142 +/- 6 mmHg, respectively, vs. control: 105 +/- 4 mmHg; HR to 407 +/- 15 and to 412 +/- 18 beats per minute (bpm), respectively, vs. control: 352 +/- 12 bpm; and renal, mesenteric and hindquarter vascular resistances. However, in rats with the CVLM bilaterally blocked by muscimol, additional injections of kyn into the NTS reduced MAP to 88 +/- 5 mmHg and mesenteric and hindquarter vascular resistances below control baseline levels. Moreover, in rats with the glutamatergic mechanisms of the NTS blocked by bilateral injections of kyn, additional injections of muscimol into the CVLM also reduced MAP to 92 +/- 2 mmHg and mesenteric and hindquarter vascular resistances below control baseline levels. Simultaneous blockade of NTS and CVLM did not modify the increase in HR but also abolished the increase in renal vascular resistance produced by each treatment alone. the results suggest that important pressor mechanisms arise from the NTS and CVLM to control vascular resistance and arterial pressure under the conditions of the present study.
Palavra-chave ventrolateral medulla
gamma
gamma-aminobutyric acid
L-glutamate
muscimol
sympathetic system
Idioma Inglês
Data de publicação 2005-11-01
Publicado em American Journal of Physiology-regulatory Integrative and Comparative Physiology. Bethesda: Amer Physiological Soc, v. 289, n. 5, p. R1416-R1425, 2005.
ISSN 0363-6119 (Sherpa/Romeo, fator de impacto)
Publicador Amer Physiological Soc
Extensão R1416-R1425
Fonte http://dx.doi.org/10.1152/ajpregu.00053.2005
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000232528200025
Endereço permanente http://repositorio.unifesp.br/handle/11600/28522

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