Catecholamine-synthesizing enzymes in paraganglia of aged Fischer-344 rats. Immunohistochemistry and fluorescence microscopy.
The catecholamine-synthesizing enzymes, tyrosine hydroxylase, dopamine-beta-hydroxylase and phenylethanolamine-N-methyltransferase were examined by immunohistochemistry in hypertrophied paraganglia of aged male Fischer-344 rats. All paraganglionic cells reacted with antibodies against tyrosine hydroxylase. Dopamine beta-hydroxylase was identified in most paraganglionic cells, indicating that they synthesized norepinephrine. A variable number of paraganglia were positive for phenylethanolamine-N-methyltransferase, which suggested that they synthesized epinephrine. The formaldehyde-induced fluorescence method demonstrated greenish-yellow fluorescence or yellowish-brown fluorescence. The intensity of the fluorescence was in the same range as in adrenal medullary cells. The observations indicate that paraganglia are capable of synthesizing epinephrine.
D000818:Animals; D002838:Chromaffin System / Q000201:enzymology*; D004299:Dopamine beta-Hydroxylase / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008856:Microscopy, Fluorescence; D010233:Paraganglia, Chromaffin / Q000201:enzymology*; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344 / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D014446:Tyrosine 3-Monooxygenase; D004299:Dopamine beta-Hydroxylase; D010625:Phenylethanolamine N-Methyltransferase