Denervation supersensitivity and the delay phenomenon.

We have reviewed the denervation supersensitivity-AV shunt hypothesis (explaining the delay phenomenon) and assessed the contribution of each of the two components of denervation supersensitivy to delay. We concluded that adrenergic denervation supersensitivity contributes little to the delay phenomenon. We propose a new hypothesis, based on the effects of prolonged vascular smooth muscle relaxation in the precapillary arterioles, to explain the delay phenomenon.