Thyrotropin-releasing hormone (TRH)-immunoreactive boutons and nerve cell bodies in the dorsal horn of the cat L7 spinal cord.

With the use of the peroxidase-anti-peroxidase (PAP) technique, thyrotropin-releasing hormone (TRH)-like immunoreactivity was found in axon terminals and cell bodies in the dorsal horn of the cat spinal cord L7 segment. In particular, a conspicuous band-shaped region of axon terminals was observed in laminae II and III, while the cell bodies were most frequent in lamina III. Electron microscopic analysis showed that the TRH-immunoreactive terminals made synaptic contacts with cell bodies and dendrites of various sizes.