Inhibition of L-type calcium channels by Bisphenol A in rat aorta smooth muscle

Bisphenol A (BPA) is an endocrine disrupting chemical used on a wide range in industry. This compound has been used in the production of polycarbonate plastics and epoxy resins. For this reason and their global use, BPA is one of the most common environmental chemicals to which humans are exposed. This exposure can cause several adverse health outcomes, including at the cardiovascular level. The regulation of ion channels in vascular smooth muscle is pivotal and important for vasoreactivity, and changes in their flux can be involved in the pathophysiology of some cardiovascular diseases. This study aims to analyse in rat aorta whether the vasorelaxant effect of BPA is mediated by L-type Ca²⁺ channels inhibition. Using male Wistar rat aorta artery rings in the organ bath we analysed the contractility, and to study the activity of calcium current in A7r5 cells we used the whole cell configuration of Patch Clamp technique. Regarding the contractility experiences we observed that in both NA and KCl contraction, BPA caused a rapid and concentration-dependent relaxation. The electrophysiology experiments showed that BPA inhibited the basal and BAY K8644-stimulated whole-cell L-type Ca²⁺ channel (W-CLTCC) currents, indicating that this drug blocks the L-type Ca²⁺ channels. Our results suggest that BPA inhibits the W-CLTCC, leading to the relaxation of vascular smooth muscle.