Partial deafferentation of cat spinal neurons results in permanent changes in cell surface molecular expression and metabolic activity.

Partial denervation of spinal neurons often results in reactive reinnervation by spared systems and some recovery of function. Dorsal rhizotomy in the adult cat has been used for the examination of the molecular modifications that occur postsynaptically and which may underlie anatomical and behavioral plasticity. We examined two markers of postsynaptic neurons in the spinal cord. Immunolocalization of a specific marker of superficial dorsal horn and intermediolateral neurons, the limbic system-associated membrane protein (LAMP), revealed that removal of certain afferents results in a permanent decrease in LAMP expression. Cytochrome oxidase, a metabolic marker, is normally high in the neurons of Clarke's nucleus, but showed a dramatic decrease after deafferentation. Reactive reinnervation occurs in many regions of the spinal cord following partial deafferentation, including Clarke's nucleus and the dorsal horn, and these changes in presynaptic input may be manifest by permanent modifications in molecular expression and metabolic activity of spinal neurons.