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|Type:||Artigo de periódico|
|Title:||Forced-swim Induces Subsensitivity To Phenylephrine In The Rat Thoracic Aorta [a Natação Forçada Induz Subsensibilidade à Fenilefrina Em Aorta Torácica De Rato]|
|Author:||Sampaio Moura M.J.C.|
De Quintal M.M.
|Abstract:||Stress may change vascular function. The aim of this report was to study the sensitivity to phenylephrine (PHE) in the thoracic aorta from rats submitted to forced-swim. Male Wistar rats (200-250 g) were submitted to three swimming sessions, one session/day (15, 30 and 30 min, respectively). Immediately after the last swimming session, the animals were sacrificed and thoracic aorta was isolated. Aortic rings (3-5 mm), with and without endothelium, were carefully obtained and were maintained in Krebs-Henseleit solution (95% O 2 - 5% CO 2, 37 °C). Endothelial integrity was assessed by relaxation to acetylcholine (10 μM) in pre-contracted rings (PHE 0.1 μM). Concentration-effect curves to PHE were obtained (n = 5/group). There was no difference between control and stress groups in the maximum response to PHE of aortic rings with and without endothelium (p>0.05). Forced-swim induced subsensitivity to PHE in aortic rings with endothelium isolated from stressed rats (pD 2 = 6.89 ± 0.07; p<0.05) compared to the control group (pD 2 = 7.39 ± 0.06), without changes in aortic rings without endothelium. The in vitro inhibition of nitric oxide synthesis cancelled this subsensitivity. It is concluded that forced swim-induced-subsensitivity to PHE in thoracic aorta from rats seems to be caused by an increase in the activity of the endothelial nitric oxide system.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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