Aconitine mediates connexin43 and PKC phosphorylation status in cultured ventricular myocytes of neonatal rats

Abstract

Aconitine, a strong poisonous type of alkaloid, has a pharmaceutical effect in stimulating the membranes of cardiomyocyte. However, other effects of aconitine on the Connexin43 (Cx43) and PKC expression on cardiomyocyte are unknown. In this study, we investigated whether aconitine also mediates the phosphorylation status of Cx43 and PKC in cultured ventricular myocytes of neonatal rats. The band intensity of phosphorylated Cx43 and nonphosphorylated Cx43 in cultured and aconitine-treated cardiomyocytes were determined by Western blot analysis. The changes in phosphorylation status occurring in PKC in cultures were revealed by quantitative immunofluorescent microscopy. A decreased band intensity (0.37±0.04) of phosphorylated Cx43 (P-Cx43) and a concomitant increased band intensity (3.56 ± 0.65) of nonphosphorylated Cx43 (NP-Cx43) were found, compared to the controls (1.00 for P-Cx43 and NP-Cx43). It also revealed that, after aconitine treatment, the amount of phosphorylated PKC (P-PKC ) decreased significantly. Similar changes were revealed in phosphorylation status occurring in PKC in the cultures under the same treatment conditions. These observations suggest that aconitine not only induces dephosphorylation of Cx43, but also alters expression of P-PKC in cultured cardiomyocytes.