Figure 1
From: Facilitation of synaptic transmission and pain responses by CGRP in the amygdala of normal rats
CGRP enhances synaptic transmission in the CeLC in slices from normal animals. (A) Monosynaptic EPSCs evoked at the PB-CeLC synapse with increasing stimulus intensities before and during CGRP (100 nM, 12 min). Individual traces are the average of 10 EPSCs. (B) CGRP (100 nM, 10-14 min) increased input-output function of the PB-CeLC synapse significantly (n = 10, P < 0.0001, F1,198 = 67.97, two-way ANOVA). Input-output curves were generated by plotting peak EPSC amplitude (pA) as a function of afferent fiber volley stimulus intensity (μA). (C) Synaptic facilitation by CGRP was blocked by co-administration of a CGRP1 receptor antagonist (CGRP8-37, 1 μM). Individual traces are the average of 8-10 EPSCs. (D) Cumulative concentration-response relationship of CGRP effects on synaptic transmission at the PB-CeLC synapse (n = 15). Peak amplitudes of monosynaptic EPSCs were averaged for each concentration of CGRP and expressed as percent of predrug control (set to 100%). Concentration-response curve was obtained by non-linear regression analysis using the formula y = A+(B-A)/[1+(10C/10X)D], where A is the bottom plateau, B top plateau, C = log(IC50), and D is the slope coefficient (GraphPad Prism software). CGRP8-37 (1 μM, n = 6) blocked the effect of CGRP (100 nM). CeLC neurons were recorded at -60 mV in slices from naïve untreated animals. Symbols and error bars represent mean ± SEM. *, **, *** P < 0.05-0.001 (Bonferroni posttests).