Experimental spinal cord injury: effects of trauma or ischemia on TRH and muscarinic receptors.

Traumatic spinal cord injury in rats and ischemic spinal cord injury in rabbits were associated with time-dependent, localized decreases in thyrotropin-releasing hormone (TRH) and muscarinic receptor binding. Changes were not evident in the first 24 to 48 hours, consistent with the hypothesis that secondary alterations in spinal cord may occur relatively late after injury. TRH receptor binding, but not muscarinic receptor binding, recovered by 3 weeks following trauma. Since TRH and acetylcholine may serve as excitatory neurotransmitters within the spinal cord, such changes could contribute to the functional neurologic impairment that follows injury.