Gao Xiao-Lei, Yin Gui-Dong, Bing Yan-Hua, Jin Yuan-Zhe, Jin Qing-Hua
Department of Physiology and Pathophysioligy, Yanbian University Medical College, Yanji 133000, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2009 Nov;25(4):462-6.
To investigate the possible involvement of gamma-aminobutyric acid (GABA) in the paraventricular nucleus (PVN) in cardiovascular responses induced by central salt loading.
Direct perfusion into PVN region with hypertonic saline (0.6 mol/L) was performed in conscious rats by using an in vivo brain microdialysis technique. Then, the extracellular concentration of GABA in the PVN region was measured by microdialysis and high performance liquid chromatography (HPLC) techniques, and the blood pressure (BP) and heart rate (HR) were with recorded simultaneously. Bicuculline (an antagonist of GABAA receptor) or saclofen (an antagonist of GABAB receptor) were coperfused hypertonic saline into PVN region, then the cardiovascular responses were examined.
(1) The local perfusion of 0.6 mol/L saline elicited significant increases on BP and HR (P < 0.01). In addition, perfusion of 0.6 mol/L saline increased the extracellular GABA levels in the PVN region, which reached 561.96% +/- 173.96% (P < 0.05) of the basal level. (2) Bicuculline or salcofen significantly attenuated the in-response of BP (P < 0.01, respectively), whereas the antagonists did not influence the response of HR induced by hypertonic saline.
Local perfusion of hypertonic saline in the PVN region elicits a local release of GABA, which may act via GABA(A) and GABA(B) receptors to produce pressor response.
探讨γ-氨基丁酸（GABA）在室旁核（PVN）中是否参与中枢性盐负荷诱导的心血管反应。
采用体内脑微透析技术，对清醒大鼠的PVN区域直接灌注高渗盐水（0.6mol/L）。然后，通过微透析和高效液相色谱（HPLC）技术测量PVN区域细胞外GABA浓度，同时记录血压（BP）和心率（HR）。将荷包牡丹碱（GABAA受体拮抗剂）或舒氯芬（GABAB受体拮抗剂）与高渗盐水共同灌注到PVN区域，然后检测心血管反应。
（1）0.6mol/L盐水局部灌注可使BP和HR显著升高（P<0.01）。此外，0.6mol/L盐水灌注可使PVN区域细胞外GABA水平升高，达到基础水平的561.96%±173.96%（P<0.05）。（2）荷包牡丹碱或舒氯芬可显著减弱BP的反应（分别为P<0.01），而拮抗剂对高渗盐水诱导的HR反应无影响。
PVN区域局部灌注高渗盐水可引起GABA局部释放，其可能通过GABA(A)和GABA(B)受体发挥作用，产生升压反应。
