Small fluorescent cells in the rat kidney contain 5-hydroxytryptamine not a catecholamine.
The rat kidney contains and excretes more dopamine than can be attributed solely to its originating from intrarenal noradrenergic nerves and plasma-free dopamine. It has recently been suggested that the source of this excess dopamine may be a population of small cells that are present in the renal medulla, and which by fluorescence and electron microscopy appear to contain high concentrations of a monoamine. We have therefore further investigated these cells. After formaldehyde treatment the fluorescence of the cells was characteristic of indoleamines rather than of catecholamine-containing structures. They did not form a visible precipitate with chromium salts in the classic chromaffin reaction. DOPA decarboxylase-like immunoreactivity was present in the adrenal medulla but not in the intrarenal cells or in mesenteric mast cells. 5-hydroxytryptamine (5-HT)-like immunoreactivity was seen in the intrarenal cells and in mesenteric mast cells, but was not evident in adrenal medullary cells. These results indicate that the intrarenal cells are 5-HT-containing mast cells and do not contribute to renal dopamine production.
D000313:Adrenal Medulla / Q000032:analysis; D000818:Animals; D004296:Dopa Decarboxylase / Q000032:analysis; D004298:Dopamine / Q000032:analysis; D005260:Female; D007120:Immunochemistry; D007668:Kidney / Q000032:analysis* / Q000166:cytology; D007679:Kidney Medulla / Q000032:analysis; D008297:Male; D008856:Microscopy, Fluorescence; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000032:analysis*
D012701:Serotonin; D004296:Dopa Decarboxylase; D004298:Dopamine