Non-neuronal expression of choline acetyltransferase in the rat kidney

• Published in: Life sciences (1973) 2011-09, Vol.89 (11-12), p.408-414
• Main Authors: Maeda, Seishi, Jun, Jin Gon, Kuwahara-Otani, Sachi, Tanaka, Koichi, Hayakawa, Tetsu, Seki, Makoto
• Format: Article
• Language: English
• Subjects: Acetylcholine; Acetylcholine - metabolism; adults; Animals; Brain - metabolism; Choline; Choline acetyltransferase; Choline O-acetyltransferase; Choline O-Acetyltransferase - metabolism; cholinergic agents; Cholinergic effect; Collecting duct; cortex; Cortical collecting duct; Enzymes; Excretion; Gene expression; Hypotension; Immunohistochemistry; in situ hybridization; Innervation; Kidney; Kidney - enzymology; Kidney - metabolism; Kidney Cortex - enzymology; Kidney Tubules, Collecting - cytology; Kidney Tubules, Collecting - enzymology; Male; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; messenger RNA; mRNA; Nephrons; Neurons - enzymology; Neurons - metabolism; Non-neuronal cell; Parasympathetic nervous system; Polymerase chain reaction; Rats; Rats, Sprague-Dawley; reverse transcriptase polymerase chain reaction; RNA - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Tubules; Vesicular Acetylcholine Transport Proteins - genetics; Vesicular Acetylcholine Transport Proteins - metabolism
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/j.lfs.2011.07.011

Acetylcholine (ACh) has been shown to increase ion and water excretion in the kidneys, resulting in hypotension. However, no evidence of renal parasympathetic innervation has been shown, and the source of ACh acting on nephrons is still unknown. The aim of the present study was to identify ACh-producing cells in the rat kidney, by examining the expression of cholinergic agents and localization of an ACh-synthesizing enzyme, choline acetyltransferase (ChAT), in the kidney. Adult mail Sprague–Dawley rats were used in this study. Expression of mRNA of cholinergic agents, ChAT, vesicular ACh transporter (VAChT), and high-affinity choline transporter (CHT-1), in the kidney was examined by RT-PCR. Localization of ChAT mRNA and protein was examined by in situ hybridization and tyramide-enhanced immunohistochemistry, respectively. RT-PCR showed the expression of ChAT, VAChT, and CHT-1. In situ hybridization demonstrated that ChAT mRNA is localized to the renal cortical collecting ducts (CCD). Immunohistochemistry showed that the ChAT-positive cells were principal cells, and that they were unevenly distributed in the tubules, and constituted approximately 15.2% of CCD in the cortex, and 3.6% and 1.5% in the outer and inner medulla, respectively. ChAT-positive immunoreactivity was localized to the apical side of principal cells, suggesting that ACh synthesis may occur in the apical compartment of these cells. These results suggest that the cholinergic effects in the nephron may be mediated at least in part by ACh originating from CCD principal cells and its expression may be locally regulated in the rat kidney.