Fig. 7.

Glutamate-activated currents in GnRH neurons.A, Current responses and current–voltage relationship of the peak responses to 1 mm glutamate (Glu). Arrow points to the responses. The patch is the same as that whose responses to 1 mm GABA are shown in Figure 6B. B, Responses to increasing concentrations of glutamate atV_h of −100 mV. Note the difference in scale compared with that in A. The patch was from a GnRH neuron in the DBB of the same mouse whose responses are shown inA. Scale is the same in this panel and inC and D. C, Inhibition of the fast desensitizing component of the glutamate response by NBQX (top traces) and responses to AMPA (middle trace) and kainate (KA; bottom trace), all at V_h of −100 mV. The NBQX-sensitive glutamate responses were from a GnRH neuron in the DBB of a P17 female GnRH-GFP mouse. The AMPA and kainate responses were from a GnRH neuron in the DBB of a 6-month-old female GnRH-GFP mouse.D, Nondesensitizing single-channel responses to glutamate in the absence (top left) and presence (top right) of a cocktail of NBQX and AP-5 atV_h values of −60, −80, and −100 mV; current–voltage relationship of the single-channel responses (bottom left); and a response to NMDA atV_h of −100 mV (bottom right). The slope of the current–voltage relationship of the single-channel events (bottom left), which is equivalent to the single-channel conductance (γ), was estimated to be ∼70 pS. The single-channel responses to glutamate (top left andright) were from a GnRH neuron neighboring the GnRH neuron whose NBQX-sensitive responses are shown in C. Response to NMDA and inhibition by AP-5 (bottom right traces) in a patch from a GnRH neuron in the DBB of a 2-month-old male GnRH-GFP mouse.