Figure 4.

The inhibition evoked by RFamide peptides from RFRP-3 and NPFF relies on Gi protein and G protein–coupled inwardly-rectifying potassium channels. Left, representative traces showing the lack of inhibition with NPFF on GnRH neurons pretreated with pertussis toxin (PTX, in A), cesium (Cs, in B) or phorbol 12-myristate 13-acetate (PMA, in C). Right, the magnitude of the effect of RFRP-3 and NPFF on GnRH neurons pretreated with PTX, Cs and PMA compared with the magnitude of the inhibition without drugs. Asterisks indicate P < .05 (1-way ANOVA and post hoc Dunnett’s multiple comparisons test). The amplitude of calcium oscillations decreased with PMA leading to a failure in peak detection rather than a true decrease in neuronal activity.