Valenti Vitor E, De Abreu Luiz Carlos, Sato Monica A, Saldiva Paulo H N, Fonseca Fernando L A, Giannocco Gisele, Riera Andreas R P, Ferreira Celso
Departamento de Medicina, Disciplina de Cardiologia, Universidade Federal de São Paulo (UNIFESP), Brazil.
J Integr Neurosci. 2011 Jun;10(2):161-76. doi: 10.1142/S0219635211002671.
In this study, we evaluated the acute effects of central NAC administration on baroreflex in juvenile SHR and Wistar Kyoto (WKY) rats. Male SHR and WKY rats (8-10 weeks old) were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. After basal MAP and HR recordings, the baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 μg/kg, bolus) and a depressor dose of sodium nitroprusside (SNP, 50 μg/kg, bolus). Baroreflex was evaluated before, 5, 15, 30 and 60 minutes after NAC injection into the 4th V. Vehicle treatment did not change baroreflex responses in WKY and SHR. Central NAC slightly but significantly increased basal HR at 15 minutes and significantly reduced PHE-induced increase in MAP 30 and 60 minutes after NAC injection (p < 0.05) in WKY rats. In relation to SHR, NAC decreased HR range 15 and 30 minutes after its administration. In conclusion, acute NAC into the 4th V does not improve baroreflex in juvenile SHR.
在本研究中，我们评估了向幼年自发性高血压大鼠（SHR）和Wistar Kyoto（WKY）大鼠脑室内注射N-乙酰半胱氨酸（NAC）对压力反射的急性影响。雄性SHR和WKY大鼠（8 - 10周龄）在第四脑室（4th V）植入不锈钢引导套管。分别将股动脉和股静脉插管用于测量平均动脉压（MAP）和心率（HR）以及输注药物。在记录基础MAP和HR后，用升压剂量的去氧肾上腺素（PHE，8μg/kg，推注）和降压剂量的硝普钠（SNP，50μg/kg，推注）测试压力反射。在向第四脑室注射NAC前、注射后5、15、30和60分钟评估压力反射。给予赋形剂处理未改变WKY和SHR的压力反射反应。在WKY大鼠中，脑室内注射NAC在15分钟时轻微但显著增加基础心率，并在注射NAC后30和60分钟时显著降低PHE诱导的MAP升高（p < 0.05）。对于SHR，NAC在给药后15和30分钟降低心率范围。总之，向第四脑室急性注射NAC不能改善幼年SHR的压力反射。
