Cocaine- and amphetamine-regulated transcript (CART) peptide immunoreactivity in myenteric plexus neurons of the rat ileum and co-localization with choline acetyltransferase

Abstract

Cocaine and amphetamine regulated transcript (CART) encodes a novel brain-enriched protein whose features are reminiscent of a neurotransmitter propeptide. We have now localized CART peptide(s) in the gastrointestinal tract by immunohistochemical methods. Polyclonal antisera raised to CART peptide 106-129 stained neuronal cell bodies and fibers in rat ileum myenteric plexus-longitudinal muscle tissue preparations. Electron microscopic analysis of thin sections showed immunopositive axon terminals in close apposition to CART-labelled and unlabelled neuronal cell bodies as well as to the longitudinal muscle. CART peptide-immunoreactive terminals contained numerous ovoid electron-lucent vesicles and a few dark-stained dense-core vesicles. Light microscopic double labelling studies revealed CART peptide immunoreactivity in a subpopulation of choline acetyltransferase (ChAT)-immunoreactive neurons. This combined light microscopic and ultrastructural examination of CART peptides in the gastrointestinal tract suggests a role of CART peptides as transmitters or neuromodulators in the peripheral nervous system.

CD81‐induced behavioural changes during chronic cocaine administration: in vivo gene delivery with regulatable lentivirus

“…β‐actin and GAPDH, used as controls, show no change in expression in all regions tested. Importantly, in agreement with earlier studies (Couceyro et al ., 1998; Fagergren & Hurd, 1999) we observed a significant increase in CART expression in the four brain regions. These data strongly confirm previous reports and clearly indicate that CD81 up‐regulation is specific for certain brain regions and that CD81 may play a major role in the response to cocaine.…”

Cocaine‐ and amphetamine‐regulated transcript: distribution and function in rat gastrointestinal tract

“…The evidence that CART is a neurotransmitter has been steadily accumulating 7 . The present study confirms and extends previous observations 4 that CART is expressed in a widespread system of enteric, preferentially myenteric, neurones. Here we report that the bulk of CART‐expressing nerve fibres is intrinsic in origin.…”

Characterization of Two Forms of Cocaine- and Amphetamine-Regulated Transcript (CART) Peptide Precursors in Goldfish: Molecular Cloning and Distribution, Modulation of Expression by Nutritional Status, and Interactions with Leptin

“…Messenger RNA encoding the CART precursor was not detected in the gastrointestinal tract of the goldfish. This is also consistent with what is known in mammals: even though stomach and intestine contain CART immunoreactivity (6,11,13,14), CART mRNA…”