Influence of TRH and TRH analogues RGH-2202 and DN-1417 on cultured ventral spinal cord neurons

It is now well established that besides its endocrine action, TRH also exerts a number of effects on the central nervous system, including the lower motor neurons of the spinal cord ventral horn. An acute, transmitter-like excitatory effect of TRH on lower motor neurons was described in animals and in patients with amyotrophic lateral sclerosis and other motor neuron disorders. We have been studying a trophic and an excitatory influence of TRH on cultured fetal-rat spinal cord neurons. In view of the rapid easy degradation of TRH by spinal cord peptidases, we have also studied a putative trophic influence of TRH analogue RGH-2202 (L-6-keto-piperidine-2 carbonyl-L-leucyl-proline-amide) (from Gideon Richter, Budapest, Hungary) and DN-1417 ( gamma -butyrolactane- gamma -carbonyl-L-histidyl-L-proline-amide) (from Takeda, Tokyo, Japan) on cultured fetal-rat ventral spinal cord neurons.