Cholecystokinin mRNA detection in rat spinal cord motoneurons but not in dorsal root ganglia neurons.

Cholecystokinin (CCK) mRNA has been detected by in situ hybridization histochemistry using two different oligonucleotide probes in small to medium-sized neurons of layers II-III and X of Rexed and in large neurons of layer IX in the rat spinal cord at cervical, thoracic and lumbo-sacral levels. No labeled cells were detected in the dorsal root ganglia. This confirms the previously established distribution of CCK-like immunoreactivity in layers II-III and X and indicates, in addition, that motoneurons of layer IX may express true genuine CCK whilst conversely, dorsal root ganglia neurons do not.