Differential expression of cocaine- and amphetamine-regulated transcript-immunoreactivity in the rat spinal preganglionic nuclei.

The distribution of cocaine- and amphetamine-regulated transcript-like immunoreactivity (CART-LI) was investigated in the rat spinal cords with the use of an antiserum against the CART peptide fragment 55-102. CART-LI fibers were concentrated in the superficial layers of the dorsal horn of all segments. In addition to CART-LI fibers, intensely labeled somata were detected in the intermediolateral cell column (IML) and other sympathetic preganglionic nuclei of the thoracolumbar segments. In the lumbosacral segments, CART-LI fibers but not somata were seen in the sacral parasympathetic nucleus. Double-labeling the spinal sections with choline acetyltransferase (ChAT)-antisera and CART-antisera revealed that the large majority of ChAT-positive somata in the sympathetic preganglionic nuclei were CART-positive, whereas ChAT-positive somata in the parasympathetic preganglionic nuclei were CART-negative. Our results show that CART-LI is selectively expressed in a population of sympathetic preganglionic neurons (SPNs), but not in parasympathetic preganglionic neurons (PPNs) of the rat.