Gamma‐aminobutyric acid B Receptor Immunoreactivity in the Mouse Adrenal Medulla

Abstract

The present study examined gamma-aminobutyric acid B (GABA B ) receptor, GABA, choline acetyltransferase (ChAT), and neuronal nitric oxide synthase (nNOS) immunoreactivities in the mouse adrenal medulla. GABA B receptor immunoreactivity was seen in numerous chromaffin cells and in a few ganglion cells of the adrenal medulla. By using a formaldehyde-induced fluorescence (FIF) method, GABA B receptor immunoreactivity was observed in numerous adrenaline (A) cells, but not in noradrenaline (NA) cells showing blue-white fluorescence. This suggests that GABA B receptors may be present in the A cells and be related to the secretory activity of A cells but not NA cells in the mouse adrenal medulla. GABA B receptor immunoreactive ganglion cells were shown to be nNOS immunopositive by using a double immunostaining method. Weak GABA immunoreactivity was visible in some chromaffin cells and in the numerous nerve fibers of the medulla. By using the FIF method, weak GABA-immunoreactive chromaffin cells were shown to be in the NA cells showing blue-white fluorescence. GABA-immunoreactive nerve fibers were in dense contact in A cells, but not NA cells. GABA-immunoreactive nerve fibers closely contacted a few ganglion cells. Numerous GABA-immunoreactive nerve fibers in the medulla showed ChAT immunoreactive. This result suggests that GABA and acetylcholine may be released from the same nerve fibers and may have a secretory effect on the A cells of the medulla. Anat Rec, 296:971-978, 2013.

Expression and localization of pChAT as a novel method to study cholinergic innervation of rat adrenal gland

“…In partial agreement, ChAT-IR nerve fibers formed a dense meshwork and some of the intramedullary nerve cell bodies were ChAT-IR in rat (Kato et al, 2014), guinea pig and mouse (Colombo-Benkmann et al, 1995;Oomori et al, 2013). Although the presence of neurons in the adrenal medulla has been recognized in many laboratory and domestic animals (Coupland, 1965a;Tomlinson and Coupland, 1990), no immunohistochemical studies of these elements against acceptable cholinergic markers have been published.…”

“…The presence of cholinergic nerve fibers in the adrenal glands has been studied in rat (Purwar, 1978;Parker et al, 1993;Janossy et al, 1998;Murabayashi et al, 2009), mouse (Oomori et al, 2013), guinea pig (Parker et al, 1990), cow (De Diego, 2010, goat (Watanabe et al, 1990), pig (Tornøe et al, 2000), and human (Charlton et al, 1991) using different markers. Additionally the vagal innervation of the adrenal gland of guinea pig and rat (Coupland et al, 1989;Tomlinson and Coupland, 1990) and the observation of AChE-positive neurons of rat adrenal medulla (Coupland and Holmes, 1958;Coupland, 1965a;Tomlinson and Coupland, 1990) support the localization of cholinergic nerve fibers in the adrenal glands.…”