A possible Ca2+-induced Ca2+ release mechanism mediated by norepinephrine in vascular smooth muscle

In vascular smooth muscle, the norepinephrine-sensitive Ca2+ store is distinct from the sarcoplasmic reticulum. Under physiological conditions, Ca2+ released from the norepinephrine-sensitive store may induce Ca2+ release from the sarcoplasmic reticulum, i.e. norepinephrine mediated activation may involve a Ca2+-induced Ca2+ release mechanism.