Attenuated pressor responses to amino acids in the rostral ventrolateral medulla after swimming training in conscious rats

Attenuated pressor responses to amino acids in the rostral ventrolateral medulla after swimming training in conscious rats

Author Martins-Pinge, M. C. Google Scholar
Becker, L. K. Google Scholar
Garcia, MRL Google Scholar
Zoccal, D. B. Google Scholar
Neto, R. V. Google Scholar
Basso, L. S. Google Scholar
Souza, HCD de Google Scholar
Lopes, O. U. Google Scholar
Institution Universidade Estadual de Londrina (UEL)
Universidade Federal de São Paulo (UNIFESP)
Abstract The cardiovascular effects of microinjection of the amino acids glutamate and glycine within the rostral ventrolateral medulla (RVLM) after swimming training (ST) in unrestrained awake rats were investigated. Unilateral microinjection of L-glutamate (5, 20 and 50 MM, in 100 nl) produced a dose dependent increase in mean arterial pressure (MAP) in control (C) (16 +/- 5 mm Hg; 29 +/- 6 min Hg; 43 +/- 6 mm Hg) and swim (SW) (1 +/- 1 mm Hg; 16 2 mm Hg; 25 3 min Hg) groups. However, the magnitude of this response was lower in the swim group. Prazosin injection produced hypotension and tachycardia in both groups (C = -43 +/- 3 mm Hg/98 +/- 16 bpm; SW = -61 +/- 5 mm Hg/115 +/- 32 bpm). in the SW group the hypotension caused by prazosin was greater compared to C group, but the tachycardia was not different between them. After prazosin, glutamate response in RVLM was blocked in both groups as well. When glycine (10 mM or 1 M, in 100 nl) were microinjected into the RVLM of C group we observed two different effects: decrease in MAP with the lower dose and an increase in MAP with the higher dose (10 mM = -13 +/- 2 mm Hg; 1 M = 47 +/- 6 mm Hg). However, after ST the hypertensive response to glycine was blunted with no alterations in the hypotensive response (10 mM = -14 +/- 1 mm Hg; 1 M = 18 +/- 4 mm Hg). These findings suggest that RVLM is involved in the modulation of the sympathetic outflow to the cardiovascular system during exercise training. (c) 2005 Elsevier B.V. All rights reserved.
Keywords blood pressure
exercise training
sympathetic nervous system
glutamate receptors
Language English
Date 2005-10-30
Published in Autonomic Neuroscience-basic & Clinical. Amsterdam: Elsevier B.V., v. 122, n. 1-2, p. 21-28, 2005.
ISSN 1566-0702 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 21-28
Origin http://dx.doi.org/10.1016/j.autneu.2005.07.007
Access rights Closed access
Type Article
Web of Science ID WOS:000233154800003
URI http://repositorio.unifesp.br/handle/11600/28513

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