TY - JOUR
T1 - Comparative effects of angiotensin II on the contractility of muscularis mucosae and detrusor in the pig urinary bladder
AU - Lim, Iris
AU - Mitsui, Retsu
AU - Kameda, Masashi
AU - Sellers, Donna Jayne
AU - Chess-Williams, Russ
AU - Hashitani, Hikaru
N1 - © 2020 Wiley Periodicals LLC.
PY - 2021/1
Y1 - 2021/1
N2 - To explore contractile actions of angiotensin II (ATII) on the muscularis mucosae (MM) of the bladder, ATII-induced contractions were compared between MM and the detrusor smooth muscle (DSM) of the pig bladder by isometric tension recordings. Effects of ATII on spontaneous Ca2+ transients in MM were visualized using Cal-520 fluorescence. ATII receptor type 1 (ATR1) expression in MM and DSM was also examined by immunohistochemistry. ATII (1 nM–1 μM) caused phasic contractions of MM in a concentration-dependent manner, while ATII (10 nM–10 μM) had no or marginal effects on DSM contractility. ATII (100 nM)-induced MM contractions had an amplitude of approximately 70% of carbachol (1 μM)-induced or 90% of U46619 (100 nM)-induced contractions. Candesartan (10 nM), an ATR1 blocker, prevented the contractile effects of ATII (1 nM) in MM, while ATR1 immunofluorescence was greater in MM than DSM. ATII (10–100 pM) increased the frequency but not the amplitude of spontaneous Ca2+ transients in MM. Both urothelium-intact and -denuded MM strips developed comparable spontaneous phasic contractions, but ATII, carbachol and U46619-induced contractions were significantly larger in urothelium-denuded than urothelium-intact MM strips. In conclusion, the MM appears to have a much greater sensitivity to ATII compared with DSM that could well sense circulating ATII, suggesting that MM may be the predominant target of contractile actions induced by ATII in the bladder while the urothelium appears to inhibit MM contractility.
AB - To explore contractile actions of angiotensin II (ATII) on the muscularis mucosae (MM) of the bladder, ATII-induced contractions were compared between MM and the detrusor smooth muscle (DSM) of the pig bladder by isometric tension recordings. Effects of ATII on spontaneous Ca2+ transients in MM were visualized using Cal-520 fluorescence. ATII receptor type 1 (ATR1) expression in MM and DSM was also examined by immunohistochemistry. ATII (1 nM–1 μM) caused phasic contractions of MM in a concentration-dependent manner, while ATII (10 nM–10 μM) had no or marginal effects on DSM contractility. ATII (100 nM)-induced MM contractions had an amplitude of approximately 70% of carbachol (1 μM)-induced or 90% of U46619 (100 nM)-induced contractions. Candesartan (10 nM), an ATR1 blocker, prevented the contractile effects of ATII (1 nM) in MM, while ATR1 immunofluorescence was greater in MM than DSM. ATII (10–100 pM) increased the frequency but not the amplitude of spontaneous Ca2+ transients in MM. Both urothelium-intact and -denuded MM strips developed comparable spontaneous phasic contractions, but ATII, carbachol and U46619-induced contractions were significantly larger in urothelium-denuded than urothelium-intact MM strips. In conclusion, the MM appears to have a much greater sensitivity to ATII compared with DSM that could well sense circulating ATII, suggesting that MM may be the predominant target of contractile actions induced by ATII in the bladder while the urothelium appears to inhibit MM contractility.
UR - http://www.scopus.com/inward/record.url?scp=85092709279&partnerID=8YFLogxK
U2 - 10.1002/nau.24548
DO - 10.1002/nau.24548
M3 - Article
C2 - 33074588
AN - SCOPUS:85092709279
SN - 0733-2467
VL - 40
SP - 102
EP - 111
JO - Neurourology and Urodynamics
JF - Neurourology and Urodynamics
IS - 1
ER -