Stretch-activated currents in cardiomyocytes isolated from rabbit pulmonary veins

Evidence is growing of a relationship between atrial dilation and atrial fibrillation (AF), the most prevalent type of arrhythmia. Pulmonary veins, which are important ectopic foci for provoking AF, are of increasing interest in relation to the early development of AF. Here, using single cardiomyocytes isolated from rabbit pulmonary veins, we characterised the stretch-activated currents induced by swelling and axial mechanical stretching. Swelling induced both a stretch-activated nonselective cationic current (NSC) and a Cl − current. The swelling-induced Cl − current ( I Cl,swell) was inhibited by DIDS, whereas the swelling-induced NSC ( I NSC,swell) was inhibited by Gd 3+. The cationic selectivity of the I NSC,swell was K +>Cs +>Na +>Li +, whilst the P K/P Na, P Cs/P Na, and P Li/P Na permeability ratios were 2.84, 1.86, and 0.85, respectively. Activation of the I NSC,swell was faster than that of the I Cl,swell. Given a high K + concentration in the bath solution, the I NSC,swell showed limited amplitude (