Calcium influx and postjunctional supersensitivity in guinea pig aortic strips.

Both reserpine and 6-hydroxydopamine (6-OHDA) pretreatment potentiated the sensitivity of guinea pig aortic strips to norepinephrine (NE), barium, methoxamine and potassium indicating postjunctional supersensitivity. However, cocaine treatmetn only potentiated the NE response indicating prejunctional supersensitivity. 6-OHDA and reserpine-induced supersensitivity but not cocaine-induced supersensitivity was accompanied by an increase in 45Ca influx.