Temperature-induced transitory and steady-state changes in the calcium current of guinea pig ventricular myocytes

Abstract
ICa was recorded in quinea pig ventricular myocytes using the whole-cell voltage-clamp technique. The shape of the I–V relation was unaffected by temperature (21–37°C) but there were large changes in ICa amplitude and time course. Steady-state responses indicated Q10 's of 2.96±0.14 (amplitude), 2.52±0.13 (time to peak), and 2.82±0.28 (T1/2 inactivation) (mean ± SD, n=6). Quick changes in temperature (T1/210 relations (early depression, compensatory overshoot). Thus, cardiac ICa differs from other currents in having a high amplitude-Q10 and an oscillatory response to rapid temperature changes.