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

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 PKCα expression on cardiomyocyte are unknown. In this study, we investigated whether aconitine also mediates the phosphorylation status of Cx43 and PKCα 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 PKCα 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 PKCα (P-PKCα) decreased significantly. Similar changes were revealed in phosphorylation status occurring in PKCα 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-PKCα in cultured cardiomyocytes.   Key words: Aconitine, cardiomyocyte, connexin 43 (Cx43), protein kinase C-α (PKCα), protein phosphorylation.