Enhanced neurally evoked responses and inhibition of norepinephrine reuptake in rat mesenteric arteries after spinal transection

Abstract

In patients with high thoracic spinal lesions that remove most of the central drive to splanchnic preganglionic neurons, visceral or nociceptive stimuli below the lesion can provoke large increases in blood pressure (autonomic dysreflexia). We have examined the effects of T4 spinal transection on isometric contractions of mesenteric arteries isolated from spinalized rats. Nerve-evoked contractions involved synergistic roles for norepinephrine and ATP. At 7 wk after spinal transection, responses to perivascular stimulation at 1-5 Hz were enhanced five-fold, whereas the α1-adrenoceptor antagonist prazosin (10 nM) produced a twofold larger reduction in contraction (to 20 pulses at 10 Hz) than i..