[3H]GABA uptake and GABA localization in mucosal endocrine cells of the rat stomach and colon.

The aim of this study was to characterize the distribution of GABAergic cells in the rat gut mucosa. Thin and/or thick serial sections of segments of rat antrum and distal colon were treated for autoradiographic localization of sites of [3H]GABA (50 nM) high-affinity uptake, or GABA immunoreactivity. Dense accumulations of silver grains were localized to a discrete population of granulated mucosal cells. These appeared to be D-type endocrine cells. These gut regions also displayed strongly GABA-immunoreactive mucosal cells. These results confirm the presence of GABAergic cells in the rat antral mucosa, and reveal that [3H]GABA is accumulated by mucosal endocrine cells in the rat colon.