Effects of spinal cord stimulation on cerebrovascular flow: role of sympathetic and parasympathetic innervations.

Objective Cervical spinal cord stimulation (SCS) has been found to augment cerebral blood flow (CBF) in a number of animal models. However, the effective use of SCS is hampered by a lack of understanding of its mechanism(s) of action. In this paper, we focus on the sympathetic and parasympathetic effects of SCS on CBF. Method Sprague-Dawley rats were selected for the experimental series.The animals were divided into 5 groups to underwent SCS and laser Doppler flowmeter (LDF) recordings. Control group, the animal underwent SCS and LDF recordings without any surgery of the nerve fibers and ganglia. V1 group, the animal underwent bilateral resection of the nasociliary and post-ganglionic parasympathetic nerve fibbers. SCG group, the animal underwent bilateral resection of supper cervical ganglion. V1 + SCG group, the animal underwent both surgeries as V1- and SCG-group animals did. Sham group, the animal underwent the carotid manipulation with blunt-tipped forceps as well as the dissection of nasociliary and post-ganglionic parasympathetic nerve fibers around the ethmoidal foramen, but without cutting any nerves. Results During the SCS, the LDF was no statistical difference between the V1 or SCG group and the control group. Yet, the effects of SCS on CBF are completely abolished in V1 + SCG group. Conclusions Surgical interruption of both the parasympathetic and sympathetic pathways has the contradict effect on SCS-induced CBF augmentation.