Changes in mechanical responsiveness of the rat aorta after cervical spinal cord stimulation.

The effect of cervical spinal cord stimulation on the mechanical vascular responsiveness of rat aortic artery rings was studied "in vitro". Arteries with and without endothelium from sham and stimulated male Wistar rats were placed in an organ bath studying the contractile response induced by noradrenaline, prostaglandin F2 alpha and serotonin. For spinal cord stimulation two electrodes were placed in the cervical epidural space using microsurgical technique. The parameters of stimulation were: monophasic waveform current, pulse width of 0.1 ms, frequency of 120 cps, and intensity one third of the threshold which produced motor responses (between 0.3 and 0.5 v). The total period of stimulation was 120 minutes. The potency of each vaso-active agent was calculated in the organ bath for each experimental group. There were differences only when arteries with endothelium from sham (7.2587 +/- 0.2308) and stimulated (8.0720 +/- 0.3723) rats were tested with noradrenaline (p less than 0.01). Our results suggest that cervical spinal cord stimulation induces changes in the vascular wall that might explain the effects of spinal cord stimulation on vasomotor control.