Aims: Cocaine- and amphetamine-regulated transcript (CART)-peptide is found in the brain and participates in the control of feeding behavior. It is also expressed in the peripheral nervous system and is suggested to have neuromodulatory and/or neurotrophic effects in rat intestine. The aims of this study were to investigate the presence of CART-peptide in the normal ganglionic as well as aganglionic intestine from patients with Hirschsprung's disease and the peptide's possible coexistence with other neurotransmitters.
Methods: Intestinal specimens from nine patients with Hirschsprung's disease were examined using immunohistochemistry. A double immunostaining technique was used in order to elucidate the presence of CART-peptide in NOS and VIP-containing enteric neurons.
Results: In ganglionic intestine, CART-peptide was found in numerous nerve fibers, predominantly within the smooth muscle layers and in myenteric nerve cell bodies. A high degree of co-localization of CART with NOS and VIP was seen. Only very few CART immunoreactive nerve fibers and no nerve cell bodies were found in the aganglionic intestine.
Conclusions: This is the first report on the presence of CART-peptide in the human intestine. In the ganglionic intestine CART was detected mainly in myenteric neurons, while only very few CART-IR nerve fibers were found in the aganglionic intestine. This, together with the coexistence of CART with NOS and VIP, indicates an intrinsic origin of the CART-containing neurons and suggests that CART may influence NO and VIP-induced effects.