Figure 6.

Na⁺ spikes evoke Ca²⁺ rises in GnRH neuron dendrites. A, Confocal stack of a Rhod-2 loaded GnRH neuron. The inset shows a region of dendrite 458 μm from the soma that was line scan imaged. B, C, Ca²⁺ transients recorded from the neuron shown in A in response to either a single spike or three spikes evoked by depolarizing current injection at the soma. D, There is a trend for larger peak Ca²⁺ transients in more distal regions of GnRH neuron dendrites. Each data point is taken from a different cell (n = 27). E, Local puff application of TTX to the dendrite produces a robust inhibition in the spiking-induced Ca²⁺ transient. Response shown is from a single cell. F, Summary data showing the percentage of the spike-evoked dendritic Ca²⁺ transient that remained after various pharmacological manipulations. All treatments resulted in a significant (p < 0.05) reduction in peak transient amplitude. Error bars indicate SEM.