Figure 4.

4-Aminopyridine-sensitive current in freshly isolated smooth muscle cells of the guinea-pig carotid artery. Left panel: original traces of the large outward current observed in the presence of very low concentration of intracellular calcium for a step depolarization from −100 to 40 mV and its inhibition by the presence of 4-aminopyridine (4-AP: 5 mM, whole cell configuration of the patch-clamp technique). Right panel: Current-voltage relationship of the 4-aminopyridine-sensitive current (n=7).