EFFECTS OF INSULIN ON POTASSIUM CURRENTS OF RAT VENTRICULAR MYOCYTES IN STREPTOZOTOCIN DIABETES

Membrane currents of ventricular cardiomyocytes isolated from control, diabetic and insulin-treated diabetic Wistar rats have been measured using the whole cell configuration of the patch-clamp technique. Insul in restored the density of the 4-aminopyridine-sensitive early transie nt component of the calcium-independent outward potassium currents whi ch decreased in diabetes. The inactivation rate of the transients incr eased in diabetes and was normalised by insulin. The late 4-aminopyrid ine-insensitive component of the outward currents showed the same diab etes- and insulin-related changes. This current could reflect the acti vation of the delayed rectifier channels although pharmacological iden tification of this component could not be achieved.