Cell experiment:

HEK293 cells or HEK293T cells are used throughout the study. Average time courses of Ca2+ responses induced by 100 μM UTP with Pyr3 at indicated concentrations (0.1, 1, 3, 10 μM) in TRPC-transfected HEK293 cells are tested[1].

Pyr3 is a selective inhibitor of transient receptor potential canonical channel 3 (TRPC3), with an IC50 of 700 nM for TRPC3-mediated Ca2+ influx.

Pyr3 selectively and directly inhibits TRPC3 channels among TRPC family members. Application of Pyr3 inhibits TRPC3-mediated Ca2+ influx in a dose-dependent manner with the IC50 value of 700 nM. Pyr3 becomes apparent at 0.3 μM, and is almost complete at 3 μM. Interestingly, Ca2+ influx is inhibited by Pyr3 in cells co-expressing TRPC3 plus TRPC6 but not in cells coexpressing TRPC1 plus TRPC5. The Ang II-induced NFAT translocation is suppressed by Pyr3, but weakly by Pyr2 in a concentration-dependent manner (IC50 value was 0.05 μM for Pyr3 and 2 μM for Pyr2)[1].

References:
[1]. Kiyonaka S, et al. Selective and direct inhibition of TRPC3 channels underlies biological activities of a pyrazole compound. Proc Natl Acad Sci U S A. 2009 Mar 31;106(13):5400-5.