Mapping of the localization of Neurotensin‐Subtype‐2 Receptor expressing neurons on spinally projecting DPGi, Gi and PnC medullary neurons of the rat

Aim of investigation The neurotensin receptor 2 (NTR2) in the brain has been implicated in temperature modulation, psychostimulant effects, fear and anxiety, and basal pain modulation. The spinal anatomical projections of brainstem NTR2 expressing neurons are unknown. This study attempts to map the cell body distribution of those NTR2 expressing brainstem neurons that project to the dorsal horn of the spinal cord, and which are believed to be important in pain modulation. Methods Fluorogold retrolabelling from the spinal cord was performed on adult male Sprague‐Dawley rats. Standard fluorescence immunohistochemical labeling of NTR2 was then performed on brainstem slices. Results and Conclusions These data indicate that the NTR2 is expressed on large medullary neurons in the DPGi, Gi and PnC. A subset of these neurons appear to project to the dorsal spinal cord. It is possible that these neurons could be responsible for a component of NTR2 induced spinal modulation of pain.