Perinuclear localization of biogenic amines (serotonin and histamine) in rat immune cells

Abstract

EDAC fixation, which polymerizes biogenic amines, and clorgyline, which blocks monoamine oxydase, were used to demonstrate the perinuclear and nuclear localization of histamine and serotonin (5-HT) of immune cells in rat peritoneal fluid and thymus. For detection, an immunocytochemical method combined with confocal microscopy was used. In peritoneal cells (lymphocytes) 5-HT formed spots around the nucleus, while histamine was localized diffusely. In thymocytes, 5-HT was distributed in patches, while histamine formed a garland around the nuclear envelope. Clorgyline enhanced the fluorescence and increased the number of fluorescent positive cells only for histamine, and then histamine-positive nuclei were also present. The results show that: (1) EDAC fixation demonstrates the presence of biogenic amines in immune cells, (2) using this fixation, the perinuclear localization of biogenic amines can be demonstrated, (3) the localization of the two amines is different and (4) the nuclear localization of histamine in thymocytes can be surmised and in mast cells (described previously) is proven again. The potential importance of the nuclear and near-nuclear localization of biogenic amines is discussed.

Systematic analysis of histamine and N-methylhistamine concentrations in organs from two common laboratory mouse strains: C57Bl/6 and Balb/c

“…Conversely, other data suggest that the thymus is necessary for the proper development of mast cell populations [17,18]. Histamine in the thymus may be produced also by cells other than mast cells [18]. Their contribution to the development of mast cells and the thymus is, however, still unclear.…”

“…Mast cells are probably involved in the development of the thymus [16]. Conversely, other data suggest that the thymus is necessary for the proper development of mast cell populations [17,18]. Histamine in the thymus may be produced also by cells other than mast cells [18].…”

Production and Function of Serotonin in Cardiac Cells

“…Moreover, it stands to reason that 5-HT produced within cardiomyocytes might also exit the cardiomyocyte wherein it was formed (speculatively using uptake 1 or 2 and/or SERT, see below) to act in an autocrine or paracrine fashion at least under pathophysiological conditions. 5-HT can be compartmentalized in relevant cells: in peritoneal mast cells from rats, 5-HT was not only present in storage vesicles but also in the nucleus [38]. It is possible that mast cells produce relevant amounts of 5-HT because they contain their own TPH1 [19].…”

“…It is possible that mast cells produce relevant amounts of 5-HT because they contain their own TPH1 [19]. Compound 48/80 can release 5-HT from mast cells and PCPA (an inhibitor of TPH activity) can reduce the levels of 5-HT in the cytosol of mast cells but not the nucleus of mast cells [38]. Likewise, clorgyline (a MAO-A inhibitor) and fluoxetine (a SERT-inhibitor) could decrease the cytosolic but surprisingly also the nuclear amounts of 5-HT in mast cells [38].…”

“…Compound 48/80 can release 5-HT from mast cells and PCPA (an inhibitor of TPH activity) can reduce the levels of 5-HT in the cytosol of mast cells but not the nucleus of mast cells [38]. Likewise, clorgyline (a MAO-A inhibitor) and fluoxetine (a SERT-inhibitor) could decrease the cytosolic but surprisingly also the nuclear amounts of 5-HT in mast cells [38]. These data argue for the existence of functionally distinct subcellular pools of 5-HT.…”