Ca2+ Influx Through Voltage- and Purinoceptor-Operated Channels Estimated from [Ca2+]C Signals (Myocytes from Guinea-Pig Urinary Bladder)

Abstract
The rise in free cytosolic calcium was studied by a combination of the techniques of microspectrofluorometry and whole-cell patch clamp. By comparing the membrane currents with their effect on [Ca2+]c, the relative importance of Ca2+ influx could be quantified for both L-type Ca2+ channels and non-selective channels activated by extracellular ATP.