Cholinergic modulation of excitatory synaptic transmission in the CA3 area of the hippocampus - PubMed (original) (raw)

The effect of external calcium on presynaptic calcium influx and synaptic strengths. A, Reduction in peak magnesium green Δ_F/F_ during application of 1 m

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Cae (horizontal line) for MF (left) and A/C (right) fibers. The control solution contained 3 m

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Cae. Insets, Averages of 10–20 Δ_F/F_ transients before, during (smallest trace), and after the application of 1 m

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Cae. Calibration: vertical, 0.2% Δ_F/F_; horizontal, 10 msec. B, Relationship between peak Δ_F/F_ and Cae in MF and A/C fibers. The relative change in Δ_F/F_ for different Caevalues was measured and normalized to that of control conditions.C, Reduction in NMDAR-mediated EPSC amplitude for MF and A/C fibers for the same reduction in Cae.Insets, Averages of 10–20 NMDAR-mediated EPSCs before, during, and after the application of 1 m

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Cae. Calibration: vertical, 20 pA; horizontal, 20 msec. D, E, The relationships between EPSC amplitude and peak Δ_F/F_ normalized to control conditions and plotted on linear scales (D) and on log scales (E). Fits in D and_E_ are to Equation 1 with EPSCmax,_K_D, and n being ≫50, 19.6, and 3.63, respectively, for the MF synapse and 14.2, 0.99, and 3.86, respectively, for the A/C synapse.