[Relationship between Cx40/43 regulating the intracellular Ca2+ concentration of vascular smooth muscle cell (VSMC) and endothelium-dependent vascular contractive response of superior mesenteric artery in rats].

OBJECTIVE

To investigate the relationship between intracellular Ca2+ concentration ([Ca2+]i) mediated by connexin 40/43( Cx40/43) of VSMC and endothelium-dependent vascular contractive response of superior mesenteric arteries (SMA) in hemorrhagic shock rats.

METHODS

Third to fifth passage culture of vascular endothelial cells (VEC) and VSMC from SD rats were used as study subject, the changes in contractive response of SMA and VSMC against hypoxia were observed. The expression of Cx40/43 in SMA,VEC,VSMC were blocked by Cx40/43 ASODN, then the effect of Cx40/43 on contractive response of hypoxic SMA and [Ca2+]i of VSMC were observed.

RESULTS

The contractive responses of SMA and VSMC after hypoxia were first increased, then decreased. Hypoxia induced calcium overload in VSMC [(82 +/- 4)% in normal control group, (115 +/- 8)% in hypoxia group at 30 min, (133 +/- 13)% in hypoxia group at 2 h]. Cx40 ASODN increased [Ca2+]i in VSMC and contractive response of SMA towards myricetin, while that of Cx43 ASODN showed opposite tendency.

CONCLUSIONS

Cx40/43 can regulate the SMA endothelium-dependent vascular contractive response through [Ca2+]i of VSMC after hemorrhagic shock.