Neurochemical coding of myenteric neurones in the human gastric fundus.

The major functions of the stomach are under the control of the enteric nervous system (ENS), but the neuronal circuits involved in this control are largely unknown in humans. Enteric neurones can be characterized by their neuromediator or marker content, i.e. by neurochemical coding. The purpose of this study was to characterize the presence and co-localization of neurotransmitters in myenteric neurones of the human gastric fundus. Choline acetyltransferase (ChAT), neurone-specific enolase (NSE), vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), substance P (SP) were detected by immunohistochemical methods in whole mounts of gastric fundus myenteric plexus (seven patients). Antibodies against ChAT and NOS labelled the majority of myenteric neurones identified by NSE (57.2 +/- 5.6% and 40.8 +/- 4.5%, respectively; mean +/- SD). The proportions of VIP- and SP-immunoreactive neurones were significantly smaller, constituting 19.6 +/- 6.9% and 16.0 +/- 3.7%, respectively. Co-localization studies revealed five major populations representing over 75% of the myenteric neurones: ChAT/-, 30.1 +/- 6.1%; NOS/-, 24.2 +/- 4.4%; ChAT/SP/-, 8.3 +/- 3.1%; NOS/VIP/-, 7.2 +/- 6.0%; ChAT/VIP/-, 4.9 +/- 2.6. Some similarities are apparent in the neurochemical coding of myenteric neurones in the stomach and intestine of humans, and between the stomach of humans and animals, but striking differences exist. The precise functional role of the neurochemically identified classes of neurones remains to be determined.