Figure 8.

Schematic diagram showing proposed frequency-dependent control of GnRH neuron firing by RP3V neurons. Neurons using GABA alone (green), kisspeptin alone (blue) and both transmitters innervate GnRH neuron cell bodies and proximal dendrites. Top, At low firing frequencies (2 Hz), RP3V neuronal populations only release GABA that generates small transient increases in GnRH neuron firing (green) and has no substantial impact upon LH secretion (red). Bottom, At higher firing frequencies (10 Hz), proposed to occur on the afternoon of proestrus, RP3V inputs to GnRH neurons now release kisspeptin (blue) to generate the preovulatory LH surge (red).