Endothelin receptor A and p66Shc regulate spontaneous Ca ²⁺ oscillations in smooth muscle cells controlling renal arterial spontaneous motion

Adaptor protein p66Shc is overexpressed in smooth muscle cells of renal resistance vessels of hypertensive salt‐sensitive rats and is involved in the regulation of renal vascular tone. We applied 2‐photon laser scanning fluorescence microscopy to analyze spontaneous dynamic fluctuations in intracellular calcium concentrations ([Ca 2+ ] i ) in smooth muscle cells embedded in the walls of freshly isolated renal resistance arteries. The amplitude, number of events, and frequency of spontaneous [Ca 2+ ] i oscillations triggered by endogenously released endothelin‐1 were recorded in smooth muscle cells of the renal arteries. Endothelin receptor A antagonist BQ123 dramatically reduced the amplitude and frequency of spontaneous Ca 2+ events, producing marked inhibition of renal vessels spontaneous motion. Spontaneous Ca 2+ fluctuations in smooth muscle cells of p66Shc knockout (p66ShcKO) rats had significantly higher amplitude than in control rats. The frequency of spontaneous [Ca 2+ ] i oscillations did not change in p66ShcKO rats, suggesting that p66Shc expression did not affect endothelin‐1 release from resident endothelial cells. Acute application of endothelin‐1 revealed significantly elevated production of the total [Ca 2+ ] i in p66ShcKO rats. Spontaneous cytosolic Ca 2+ oscillations in smooth muscle cells of renal vessels mediate their spontaneous motion via the endothelin‐1/endothelin receptor A pathway. p66Shc decreases the amplitude of individual changes in [Ca 2+ ] i , which mitigates the spontaneous motion of renal vessels.—Palygin, O., Miller, B. S., Nishijima, Y., Zhang, D. X., Staruschenko, A., Sorokin, A. Endothelin receptor A and p66Shc regulate spontaneous Ca2+ oscillations in smooth muscle cells controlling renal arterial spontaneous motion. FASEB J. 33, 2636–2645 (2019). www.fasebj.org