Gamma-aminobutyric acid (GABA) immunoreactivity in the mouse adrenal gland

Abstract

Gamma-aminobutyric acid (GABA) immunoreactivity was revealed by immunocytochemistry in the mouse adrenal gland at the light and electron microscopic levels. Groups of weakly or faintly GABA immunoreactive chromaffin cells were often seen in the adrenal medulla. By means of immunohistochemistry combined with fluorescent microscopy, these GABA immunoreactive chromaffin cells showed noradrenaline fluorescence. The immunoreaction product was seen mainly in the granular cores of these noradrenaline cells. These results suggest the co-existence of GABA and noradrenaline within the chromaffin granules. Sometimes thick or thin bundles of GABA immunoreactive nerve fibers with or without varicosities were found running through the cortex directly into the medulla. In the medulla, GABA immunoreactive varicose nerve fibers were numerous and were often in close contact with small adrenaline cells and large ganglion cells; a few, however, surrounded clusters of the noradrenaline cells, where membrane specializations were formed. Single GABA immunoreactive nerve fibers, and thin or thick bundles of the immunoreactive varicose nerve fibers ran along the blood vessels in the medulla. The immunoreaction deposits were observed diffusely in the axoplasm and in small agranular vesicles of the GABA immunoreactive nerve fibers. Since no ganglion cells with GABA immunoreactivity were found in the adrenal gland, the GABA immunoreactive nerve fibers are regarded as extrinsic in origin.

Colocalization of Gamma-Aminobutyric Acid Immunoreactivity and Acetylcholinesterase Activity in Nerve Fibers of the Mouse Adrenal Gland.

“…This result is well in consistence with the previous immunohistochemical data [22]. Previous study reported that GAD-or GABA-immunoreactivity was seen in some chromaffin cells and that GABA is synthesized and stored in the chromaffin cells, and released in response to depolarizing stimulation [1,14,16].…”

“…In the adrenal medulla, previous immunohistochemical studies demonstrated GABA-or glutamate decarboxylase (GAD)-immunoreactivity in some chromaffin cells and in numerous nerve fibers [1,14,22]. It is generally accepted that numerous cholinergic nerve fibers innervate the chromaffin cells in the adrenal medulla.…”

Heterogeneous distribution of neurocalcin-immunoreactive nerve terminals in the mouse adrenal medulla

“…After fixation by paraformaldehyde, noradrenaline cells showed blue-white fluorescence (Oomori et al 1993). We compared noradrenaline-fluorescent histochemistry with neurocalcin-immunohistochemistry (Fig.…”

GABA_A Receptor Subunit mRNAs in Rat Superior Cervical Ganglia

“…Adrenal medullary GABA A receptors have also been studied functionally [40,41]. The gland seems to contain GABA both in chromaffin granules and extrinsic nerves [42]. The adrenal medulla contains GABA A receptor ·1 and ß1-3 subunits, but not ·2 or ·3 subunits, as determined from cDNA library screening and Northern blots [43].…”