Analgesia and Spasm Control After Spinal Cord Injury

Komisaruk, Barry

Abstract

In the proposed study, spinal cord transection followed by nerve transection will be utilized in the rat to test the parent grant hypothesis that in women with complete spinal cord injury as high as T12, sensibility of the reproductive tract (e.g. cervix) persists because the hypogastric and/or vagus nerve pathways to the brain retain their integrity. Behavioral, autonomic and neuroendocrine responses to vaginocervical stimulation will be measured after spinal cord transection, after which they hypogastric and/or vagus nerves will be transected, in order to ascertain whether these nerves mediate the responses that persist after the spinal cord transection. Thus, the proposed study would extend and expand the parent grant without overlapping it.
The specific aims of the current proposal are to ascertain whether: a) Analgesia in response to vagino-cervical stimulation will persist above the level of spinal transection at L5 or T7, which blocks ascending pathways from pelvic and hypogastric nerves, respectively. We will ascertain whether subsequent bilateral transection of hypogastric and then vagus nerves will block and residual effects, b) Autonomic responses, i.e. increases in heart rate and pupil dilatation, in response to vagino-cervical stimulation will be affected by the transections of spinal cord and these nerves, c) Oxytocin release in response to vaginocervical stimulation will be affected by the transections of spinal cord and these nerves. The present application is proposed in collaboration with Carlos Beyer, Ph.D., and Rafael Cueva-Rolon, M.D., Ph.D., who provide expertise in spinal cord neurophysiology-neuropharmacology. The proposed research would provide an experimental neurological foundation on which to base interpretation of the responses to reproductive tract stimulation in women with complete spinal cord injury in the parent grant. Evidence of a role of the vagus nerve in mediating these responses would have significance for rehabilitation medicine, since it would indicate the existence of a sensory pathway via which sensory impulses from the cervix and uterus could enter the brain directly, completely bypassing the spinal cord, and thus remaining functional even in women who are complete tetraplegic. The proposed study would provide a significant opportunity to formally support the active long-term collaborative research interaction that exists between these two research groups in the U.S. and Mexico.