Figure 3.

ADP inhibits GnRH neurons directly. A, Whole-cell recordings of GnRH neurons (A₁ arrow/white star) showed an acute response to 5-μg/mL ADP applied with a pipette (A₁ gray star). Explants were fixed and stained for GnRH after recordings were completed (A₂). B, Example of spontaneously active GnRH neuron inhibited by a 4-second application of ADP (B₁), replacing the ADP in the electrode with aCSF (B₂). C, Example of GnRH neuron inhibited by a 4-second application of ADP ± TTX. D, The combined application of BIC/CNQX/AP5 (BAC) decreased the frequency of calcium oscillations in GnRH neurons. Coapplication with ADP (500 ng/mL) further decreased the neuronal activity. A representative calcium imaging recording showing spontaneous baseline oscillations in intracellular calcium levels of a GnRH neuron during 10-minute periods of BAC and BAC/ADP. Line in A₁, scratch in coverslip. Scale bar: 10μM (A1 and A2).