High‐resolution pressure myography reveals pressure‐dependent local contractile and geometric dynamics in the renal pelvis and ureter

Background and Purpose Coordinated peristalsis between the renal pelvis and ureter is critical for effective urine transport. However, intraluminal pressure impact on upper urinary tract (UUT) contractility and pharmacologic responsiveness remains poorly understood due to absence of suitable investigative methods. Experimental Approach This study introduces the first application of high‐resolution pressure myography to UUT, establishing a novel ex vivo platform enabling simultaneous, intraluminal pressure‐controlled local measurement of renal pelvic contraction frequency and amplitude and ureteral inner diameter, outer diameter, and wall thickness. To define contribution of specific Ca 2+ signaling pathways, we pharmacologically examined Ca v 1.2 L‐type, Ca v 3.x T‐type, and ryanodine receptor channels, as well as sarco/endoplasmic reticulum Ca 2+ ‐ATPase (SERCA) and neuronal involvement. Key Results Elevating intraluminal pressure from 4 to 20 mmHg increased renal pelvic contraction frequency, while amplitude markedly decreased. Ureteral wall thinning was the main structural adaptation. Nifedipine reduced renal pelvic contraction amplitude and frequency and suppressed ureter peak contraction, all with reduced efficacy under high‐pressure conditions. Ni 2+ affected renal pelvic contractility only at high concentrations and had no effect on ureteral dynamics. Ryanodine did not alter measured parameters, and Na + and N‐type Ca 2+ channels were not involved. Conclusions and Implications High‐resolution pressure myography reveals pressure‐dependent local contractile and geometric responses in UUT, including altered contraction dynamics, ureteral geometric remodeling, and specific Ca 2+ channel contributions. Ca v 1.2 channels modulate both amplitude and frequency, with wall thinning as principal acute structural adaptation. Reduced drug efficacy at high pressure highlights necessity to investigate possible pressure‐adapted therapies in obstructive uropathy.