Ion currents of cardiomyocytes in different regions of the Göttingen minipig heart.

INTRODUCTION:The Göttingen minipig is a promising model for pharmacological safety assessment and for translational research in cardiology. We have examined the main ion currents in cardiomyocytes of the minipig heart. METHODS:Cardiac cells were isolated from different cardiac regions (endo-, mid- and epicardial left ventricle and right ventricle) from Göttingen minipigs and examined using the whole cell patch clamp technique combined with pharmacological interventions. RESULTS:The inward rectifier (IK1), the delayed rectifier (IK), with the rapid and slow components, (IKr, IKs) and the L-type Ca2+ channel (ICa,L) were identified in the different regions of the heart, whereas the Ca2+-independent transient outward current (Ito1) was observed in only a few cells. IK1 was similar in the cardiac regions with a slightly lower value in the epicardial cells. IKs was smaller in epi- and endo-cardial regions. DISCUSSION:The equivalents of the main human cardiac ion currents are present in the minipig cardiomyocytes with the exception of the Ca2+-independent Ito1. The study provides further evidence that the minipig is a valid model for investigating cardiovascular pharmacology.