Fig. 4.

P4-mediated inhibition is through PgRMC1. The PgRMC1 ligand and inhibitor AG-205 caused a sharp rise in intracellular calcium in the micromolar (A, shaded area). In the nanomolar range (B, boxed area), the effect was attenuated and cells were able to return to normal PPM values. P4 rapidly inhibits GnRH neuronal activity after the application of DMSO vehicle control (C and E), but inhibition is blocked by AG-205 treatment (D and F). C and D, Representative traces from single GnRH neurons. E and F, Grouped PPM data from the responder population (E) and total population (F). N and n, Number of explants and number of GnRH neurons, respectively.