Abstract:

Objective   To investigate the change of gap junction in brain artery of spontaneous hypertension(SH) rats and its relationship with hypertension. Methods   Whole-cell patchclamp, quantitative RT-PCR and Western blot technique were used to investigate the difference in electrophysiological properties of gap junction and expressions of connexin 45 (Cx45) at mRNA and protein levels in brain artery between SH rats(n=30) and Wistar rats(n=30). Results   ① As detected by whole-cell patch-clamp technique, the membrane capacitance and membrane conductance of vascular smooth muscle cells in brain artery from SH rats were significantly higher than that from normotensive Wistar rats (P<0.05), suggesting that gap junctions coupling among VSMCs were enhanced in SH rats. ② As detected by quantitative RT-PCR technology, the level of Cx45 mRNA expression in brain artery from SH rats was significantly increased compared with that from normotensive Wistar rats (P<0.05). ③ As detected by Werstern blot technique, the expression of Cx45 protein was significantly elevated in brain artery from SH rats compared with that from normotensive Wistar rats(P<0.01). Conclusion   The upregulation of Cx45 expression can enhance gap junctional communication in vascular smooth muscle cells of brain artery from SH rats to ensure the synchronous contraction of brain artery.

Key words:  Spontaneous hypertension； Rats； Brain artery; Gap junction; Connexin; Wholecell patch clamp technique