Delayed sympathetic hyperactivity is induced by ECT in patients with schizophrenia

Anatomical studies revealed a gradient in cavernous innervation, with proximal regions exhibiting a much higher axon density than distal regions (greater than 2-fold). Following either bilateral or unilateral injury, regenerating and putative sprouting axons restored this innervation gradient. After bilateral crush, anatomical studies showed almost complete regeneration of nitrergic axons. This contrasts with the reduced nerve-evoked nitrergic responses shown by our physiological studies, but is consistent with the loss of nitric oxide sensitivity. Neither injury affected noradrenergic contractions of erectile tissue or tyrosine hydroxylase-immunoreactive nerve density. Therefore, regeneration of penile parasympathetic nitrergic axons occurs following complete denervation but the physiological outcomes are limited by changes in muscle properties that occur soon (at least within 3 weeks) after injury. Muscle deficits do not occur after unilateral lesion, which may be dependent on residual erectile function maintaining sufficient vascular perfusion. These studies suggest that pharmacological vasodilator intervention early after surgery may improve return of neuromuscular transmission after penile nerve injury. Supported by NHMRC Australia.