Caveolae Disassembly using Methyl-β-cyclodextrin Causes the Abolition of Coupling of the Caveolae and the Sarcoplasmic Reticulum in the Rat Femoral Artery

Abstract

Background: Caveolae are essential in regulating signal transduction mechanisms of ion channels in vascular tissue, including BKCa channels (maxi-K). The current study investigated the localization of maxi-K channels within caveolae. Methods: Sixteen rats were divided into two groups: A control group and a treated group, where arteries in the treated group were incubated with methyl-β-cyclodextrin (MβCD) to disassemble caveolae from artery tissue. Immunohistochemistry (IHC), immunocytochemistry (ICC), transmission electron microscopy (TEM) and Western blot techniques were used in this study. Result: IHC of intact arteries showed colocalization of maxi-K channels with caveolin-1 in smooth muscle and endothelial cells and colocalized of maxi-K channels with caveolin-3 in smooth muscle cells only. These findings were also corroborated with ICC in a single smooth muscle cell. TEM revealed caveolae covering most plasma membranes of smooth muscle and endothelial cells and showed that caveolae sit close to the sarcoplasmic reticulum only in smooth muscle cells. TEM showed incubating arteries with MβCD led to the disassembly of caveolae from artery tissue. This study concluded that maxi-K channels localize to caveolae and that caveolae abolishment by MβCD led to the abolition of the coupling of caveolae and the sarcoplasmic reticulum.