Neurochemical characteristics of calbindin-like immunoreactive coeliac-cranial mesenteric ganglion complex (CCMG) neurons supplying the pre-pyloric region of the porcine stomach.

The present study was designed to determine the distribution, morphology and co-localization of calbindin-D28k (CB) with other neuroactive substances in the coeliac-cranial mesenteric ganglion complex (CCMG) neurons supplying the prepyloric region of the porcine stomach. In all animals, a median laparotomy was performed and the fluorescent retrograde neuronal tracer Fast Blue was injected into the wall of the stomach prepyloric area. On the 28th day, all animals were euthanized and the CCMG complexes were then collected and processed for double-labelling immunofluorescence for CB and tyrosine hydroxylase (TH), galanin (GAL), somatostatin (SOM), leu 5-enkephalin (LENK), vasoactive intestinal peptide (VIP), substance P (SP) and cocaine- and amphetamine-regulated transcript peptide (CART), Immunohistochemistry revealed that 8.27±0.51% of FB-positive neurons expressed CB-like immunoreactivity. Furthermore, CB co-localized with TH, GAL and SOM in retrogradely labelled cell bodies, whereas CART, LENK, VIP and SP were detected only in nerve terminals surrounding FB+/CB+ neurons. The presence of CB in the stomach-projecting neurons may indicate the contribution of CB in the sympathetic regulation of the stomach function. Furthermore, CB-LI neurons had a catecholaminergic character and co-localized with TH, GAL and SOM, which suggests multiple functions of this neuroactive substance in the CCMG neurons supplying the porcine prepyloric area.