Figure 3.
Activation of spermatids by bitter tastants increases intracellular calcium concentrations. (A) A typical calcium response trace from the head area of a male germ cell. Spermatids were loaded with the calcium-sensitive dye Fura-2/AM (inset: image of a representative spermatid). The BTM (200 μM each of caffeine, PTC, PROP, picrotin, salicin and denatonium) was first used to identify responsive spermatids, followed by a series of concentrations of the mixture. (B) A dose–response curve from 13 responsive cells with an EC50 of 13 ± 11 μM.