ABSTRACT
I. Introduction................................................................................. 206 A. Is There a GnRH Pulse Generator?...................................... 206 B. Hypothetical Mechanisms of Burst Generation
and Synchronization ............................................................. 206 II. Genetic Targeting of Enhanced Green Fluorescent
Protein (EGFP) to Gonadotropin-Releasing Hormone (GnRH) Neurons ......................................................................... 207 A. The GnRH-EGFP Transgenic Mouse Model ........................ 207 B. Morphology of GnRH-EGFP Neurons ................................. 208 C. Preliminary Electrophysiological Observations of
GnRH-EGFP Neurons ........................................................... 209 III. Whole-Cell Recordings of Episodic Firing in GnRH-EGFP
Neurons ....................................................................................... 209 IV. Synaptic Mechanisms ................................................................. 210
A. Electrotonic Coupling of GnRH Neurons through Gap Junctions ........................................................................ 211
B. Excitatory and Inhibitory Postsynaptic Currents (EPSCs and IPSCs) ................................................................ 211
V. Acutely Dissociated GnRH-EGFP Neurons .............................. 213 A. Can a Single GnRH Neuron Generate an Episodic
Pattern of Action Potentials?................................................ 213 B. Glutamate and GABA Receptors ......................................... 214
VI. Summary and Conclusions ........................................................ 214 A. GnRH-EGFP Neurons in the Transgenic Mouse Appear
to have Normal Morphological and Electrophysiological Properties ............................................................................... 214
B. Future Directions................................................................... 215 VII. Acknowledgments ...................................................................... 216
References ............................................................................................. 216
The neuroendocrine cells responsible for the production and release of gonadotropin-releasing hormone (GnRH) integrate numerous physiological inputs and provide the final common pathway for the control of reproduction. GnRH regulates secretion of the two gonadotropic hormones — luteinizing hormone (LH) and follicle stimulating hormone (FSH).
