BIOPHYSICS AND PHYSIOLOGY OF CARDIAC CALCIUM CHANNELS

Two types of calcium channels are present in heart Cells; the two type s, L and T, can be clearly distinguished on the basis of their biophys ical and pharmacological properties. The physiological role of L-type Ca2+ channels is clear and includes mediation of processes that are vi tal to the function of normal cardiac cells, such as electrical conduc tion and excitation-contraction coupling. The physiological role of T- channels is not known, although potential involvement in pacemaker act ivity can be hypothesized on the basis of their biophysical properties . The testing of these predictions is the subject of intense research interest at present.