Figure 4.

Pharmacology of inhibitors for transmembrane adenylyl cyclases (tmACs) and phospholipase C (PLC). (A) Ca²⁺ signals induced by bourgeonal in the presence of the tmAC inhibitor SQ22536. (B) Mean amplitude of bourgeonal-induced Ca²⁺ signals in the absence and presence of 200 μM SQ22536 (four experiments). (C–E) Ca²⁺ signals induced by bourgeonal (C), progesterone (D) and ammonium chloride (NH₄Cl) (E) in the presence of the tmAC inhibitor MDL12330A. (F) Relative inhibition of the signal amplitudes by 100 μM MDL12330A (⩾4 experiments). (G) Whole-cell membrane currents in extracellular solution containing Ca²⁺ and Mg²⁺ (HS). Monovalent CatSper currents in divalent-free Na⁺-based bath solution before (NaDVF) and after intracellular alkalization by ammonium chloride (10 mM) (NaDVF+NH₄Cl) in the absence and presence of MDL12330A (100 μM). MDL12330A completely inhibited basal and alkaline-activated monovalent CatSper currents. Currents were recorded at pH_i 7.3 in the absence of intracellular divalent ions. (H) Ca²⁺ signals induced by the PLC inhibitor U73122.