Effect of U-73122 on calcium channel activity in porcine myometrial cells and pancreatic beta-cell line RINm5F
Abstract
AIM: To study the effect of U-73122, putative phospholipase C (PLC) inhibitor, on
cytosolic Ca2+ concentration ([Ca2+]i) and voltage-dependent calcium channels
(VDCC).
METHODS: To record whole cell calcium current (ICa) by perforated patch-clamp and
to measure cytosolic free calcium concentration ([Ca2+]i) with Fura-2.
RESULTS: U-73122 inhibited KCl-induced and Bay-K-8644-induced increase in [Ca2+]i
dose-dependently. U-73122 decreased markedly depolarization-induced ICa both in
RINm5F and porcine myometrial cells in a concentration-dependent manner. The
effect of U-73122 was more potent in porcine myometrial cells than that in RINm5F
cells. U-73343 (an analog of U-73122), that does not inhibit PLC, also reduced
the ICa by 50%.
CONCLUSION: U-73122 inhibited VDCC and [Ca2+]i in both RINm5F and porcine
myometrial cells.
Keywords:
cytosolic Ca2+ concentration ([Ca2+]i) and voltage-dependent calcium channels
(VDCC).
METHODS: To record whole cell calcium current (ICa) by perforated patch-clamp and
to measure cytosolic free calcium concentration ([Ca2+]i) with Fura-2.
RESULTS: U-73122 inhibited KCl-induced and Bay-K-8644-induced increase in [Ca2+]i
dose-dependently. U-73122 decreased markedly depolarization-induced ICa both in
RINm5F and porcine myometrial cells in a concentration-dependent manner. The
effect of U-73122 was more potent in porcine myometrial cells than that in RINm5F
cells. U-73343 (an analog of U-73122), that does not inhibit PLC, also reduced
the ICa by 50%.
CONCLUSION: U-73122 inhibited VDCC and [Ca2+]i in both RINm5F and porcine
myometrial cells.