Spinal Cord Electrophysiological Activities After Small Doses of TRH in Control Subjects and ALS Patients

Terminals containing TRH [1] as well as TRH receptors[2] have been identified in the ventral horn and intermediate gray matter of the human spinal cord. Their physiological role remains unknown. However, motor effects have been documented clinically after infusion of large amounts (up to 20 mg per minute) of TRH in ALS patients [3]. It is thus of interest to know if this neuropeptide is able to influence the motor system in normal man and, if so, which spinal mechanisms are involved. To study this problem, electrophysiological techniques are available which test the functioning of specific spinal circuits quantitatively. If the product acts on spinal circuits in normal subjects, another relevant question would be to establish if these modifications are the same in patients with spinal cord dysfunctions, namely in ALS. We therefore undertook a study in control subjects and compared the results with those obtained in neurological patients.