Amiloride-sensitive Na+ channels in pelvic uroepithelium involved in renal sensory receptor activation

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 1998-12, Vol.275 (6), p.1780-R1792
• Main Authors: Kopp, Ulla C, Matsushita, Kazumichi, Sigmund, Rita D, Smith, Lori A, Watanabe, Shigeru, Stokes, John B
• Format: Article
• Language: English
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.1998.275.6.r1780

Department of Internal Medicine, Department of Veterans Affairs Medical Center and University of Iowa College of Medicine, Iowa City, Iowa 52242 Stretching the renal pelvic wall increases ipsilateral afferent renal nerve activity (ARNA). This response is enhanced by inhibiting Na + -K + -ATPase with ouabain, suggesting a modulatory role for intracellular Na + in the activation of mechanosensitive neurons. The messenger RNA for -, -, and -subunits of epithelial Na + channels (ENaC) is found in collecting duct cells. Because ENaC subunits show homology with genes involved in mechanosensation, we examined whether ENaC mRNA could be found in the pelvic wall and whether the ARNA response to increased renal pelvic pressure was modulated by blockers of the Na + channel. -, -, and -subunits are present in the pelvis. The messenger RNA for the - and -subunits is readily detected by in situ hybridization throughout the uroepithelium. The ARNA response to increased renal pelvic pressure was reduced by 53 ± 10% and 40 ± 10% ( P