Figure 2.
Proposed model for the control of KNDy neuron activity to drive episodic GnRH/LH secretion. Each GnRH pulse is initiated by NKB (green) acting upon reciprocally-connected KNDy neurons to stimulate kisspeptin (blue) release. Kisspeptin drives GnRH (gray) secretion and activates unidentified GPR54/Kiss1R containing ARC neurons (orange) that reinforces the stimulatory actions of NKB on KNDy neurons. GnRH release is then terminated by the release of dynorphin (red) from KNDy neurons acting directly on KNDy neurons, GnRH neurons, and/or unidentified KOR-containing neurons. The color in each terminal indicates the biologically active transmitter (potentially due to selective expression of postsynaptic receptor) and does not reflect selective transport of that peptide to the terminal. Dashed oval represents the ARC. RDyn, KOR; RKp, GPR54/Kiss1R; RNKB, NK3R.