GABA- and glutamate-activated channels in green fluorescent protein-taggedgonadotropin-releasing hormone neurons in transgenic mice

Mice were generated expressing green fluorescent protein (GFP) under the co ntrol of the gonadotropin-releasing hormone (GnRH) promoter. Green fluoresc ence was observed in, and restricted to, GnRH-immunopositive neuronal somat a in the olfactory bulb, ganglion terminale, septal nuclei, diagonal band o f Broca (DBB), preoptic area (POA), and caudal hypothalamus, as well as GnR H neuronal dendrites and axons, including axon terminals in the median emin ence and organum vasculosum of the lamina terminalis (OVLT). Whole-cell rec ordings from GFP-expressing GnRH neurons in the OVLT-POA-DBB region reveale d a firing pattern among GFP-expressing GnRH neurons distinct from that of nonfluorescent neurons. Nucleated patches of GFP-expressing GnRH neurons ex hibited pronounced responses to fast application of GABA and smaller respon ses to L-glutamate and AMPA. One-fifth of the nucleated patches responded t o NMDA. The GABA-A, AMPA, and NMDA receptor channels on GnRH neurons mediat ing these responses may play a role in the modulation of GnRH secretory osc illations.