Fig. 3
Bath applications of DHPG stimulates mGluR5 to increase hippocampal CA1 neuron excitability. a Left, a schematic drawing of experimental condition demonstrates a neuron being recorded with bath applications of DHPG. Right, representative traces demonstrate DHPG-induced depolarization of membrane potential (upper trace) and changes in AP firing frequency and afterpotential in response to square pulse injections (40 pA, 160 pA, lower traces). Note that afterpotentials following 2 different magnitudes of current injections. b FI curve summarizes the effects of DHPG on AP firing frequency in response to square current injections (n = 16, control vs DHPG, *P < 0.05). c Bar graphs summarize the effects of DHPG on afterpotentials following 4 different square current injections (n = 5, control vs DHPG, *P < 0.05). d Bar graphs summarize the effects of DHPG on resting membrane potentials (n = 5, control vs DHPG, *P < 0.05). e Representative traces demonstrate the effects of MPEP on DHPG-induced changes of AP firing frequency and afterpotentials. f Pooled data of the mean number of spikes following 80 pA square pulse injections in each condition (DHPG, n = 14; MPEP, n = 14; LY367385, n = 16, DHPG vs MPEP, ***P < 0.001; DHPG vs LY367385, n.s., P > 0.05). g Bar graphs summarize the effects of DHPG and subsequent addition of MPEP or LY367385 on afterpotentials following 160 pA square pulse injections (DHPG, n = 7; MPEP, n = 10; LY367385, n = 7; DHPG vs MPEP, ***P < 0.001; DHPG vs LY367385, n.s., P > 0.05). h Left, a schematic drawing of experimental condition demonstrates a neuron being recorded with dendritic or somatic local applications of DHPG (250 μM). Right, representative traces demonstrate the effects of local application of DHPG on AP firing frequency and afterpotentials. Inset shows an expanded view corresponding to the box shown in the voltage traces. i Pooled data of the mean number of spikes during somatic current injection in each condition (Dend, n = 10; Soma, n = 11; Dend, Control vs DHPG, *P < 0.05; Soma, Control vs DHPG, n.s., P > 0.05)