Figure 6. Manipulation of Ca²⁺ alters differently the decay of IPSCs in LF and MF/HF neurons.

A, superimposed individual IPSCs (grey) of a LF neuron in response to single-pulse stimulation with the average IPSCs highlighted (thick traces), under the conditions of 3 mm Ca²⁺ (left) and in 8 mm Sr²⁺ (middle). Right, average IPSCs normalized to the peak. B, Sr²⁺ significantly prolonged the decay of IPSCs (n = 5). C and D, IPSCs of LF neurons in response to train stimulation (100 Hz, 20 pulses) were significantly prolonged by Sr²⁺ (8 mm) (n = 6). E–H, in MF/HF neurons, Sr²⁺ significantly prolonged IPSCs elicited with single-pulse stimulation (n = 6), but did not affect IPSCs recorded with train stimulation (100 Hz, 20 pulses) (n = 6). I and J, the decay of IPSCs of LF neurons in response to single-pulse stimulation was not affected by bath application (>5 min) of EGTA-AM (100 μm) (n = 5). K and L, in LF neurons, EGTA-AM accelerated the decay of IPSCs elicited with train stimulations (100 Hz, 20 pulses) (n = 4). M–P, EGTA-AM accelerated the decay of IPSCs in MF/HF neurons, regardless of the stimulus mode (single-pulse stimulation: n = 7, train stimulation: n = 4).