Current Research Projects
Rehabilitation of Impotency in SCI: Receptor Studies
James S. Walter, PhD
Synopsis: The goal of this study is to identify receptors in human penile corporal tissue and subsequently to quantitate and map them. This will help in the development of drugs to treat erectile dysfunction (impotence) instead of the invasive methods used at present. Also, it could provide a better understanding of drug interference with erectile function which is a common factor in considering the etiology of impotence. The functional studies of the corporal receptor system have been directed to the adrenergic and cholinergic receptors since they are the major control components in other organ systems. However, there are many other receptors such as dopamine, serotonin androgens, and acetylcholine which have not been adequately evaluated. The identification and mapping of receptors in the brain by autoradiography and radioligands has led to further therapeutic drug development and to determining the toxic or detrimental effects of drugs. Also, in any evaluation of the impotent SCI patient, medications are a consideration for their impact on the problem. Yet, there is no laboratory method for evaluating this so it remains a poorly studied area. The use of the radioligand technique could give insight to erectile dysfunction with present drugs and provide a screening method for new ones. It would also point to the development of drugs to enhance erectile function, which is an intense area of research which could benefit tremendously through an expanded knowledge of the receptors of the corporal cavernosum. In order to accomplish the goal of identifying, mapping and quantifying the receptors, transverse sections of the penis are required. These will be obtained from patients undergoing penectomy for cancer.
Microstimulator Applications for Urinary Retention Following SCI
James S. Walter, PhD
Synopsis: The objective of this project is to study in a female animal model electrical stimulation that could be applied to the problem of urinary retention that can occur before or after spinal cord injury. A model of a new type of stimulator, a microstimulator, is being investigated. This is a small device that can be inserted with a needle but has all of the components of large devices such as a battery and electrodes for stimulation. We are comparing stimulation of the bladder directly to stimulation of the plexus of nerves adjacent to the bladder. We are using chronically instrumented animals so that investigations can be conducted before and after SCI. We are testing the hypothesis that stimulation of the plexus of nerves will result in better bladder urination with less side effects such as abdominal movement than direct bladder wall stimulation. Preliminary observations indicate that the pelvic plexus is an effective site for stimulation for urinary retention. Pilot funding is being provided from the Veterans Administration for this project.