Figure 1
Depression of afferent-evoked net neuronal excitation by CAP. A) A pseudo-color image sequence of stimulation-induced net optical responses measured from a slice bathed in a control solution (left), a CAP (0.5 μM)-containing solution (center), and the control solution for recovery (right). At left bottom, superimposed time traces obtained at the black square in the schematic drawing are illustrated for the respective images. At right bottom, the spatial distributions along the dorso-ventral lines in the schematic drawings are also illustrated. B) Concentration-dependent inhibition of net neuronal excitation by CAP at the period of 0.6–1.8 ms in evoked response (circles), and of 4.8–6.0 ms (squares). The curves were drawn according to the equation I = I max /[1+(IC 50/[CAP])N] (IC50 = 0.5 μM & Imax = -30% N = 1.0 at 0.6–1.8 ms of evoked response, and IC50 = 1.7 μM & Imax = -33% N = 0.5 at 4.8–6.0 ms of evoked response) C) Changes in normalized time courses of the magnitudes of net neuronal excitation by CAP application with two different durations, 10 and 20 min (circles and squares, respectively). The period of CAP application is indicated by the bar. D) Pseudo-color image sequence of stimulation-induced net optical responses measured from a slice bathed in a control solution (left), a anandamide (50 μM)-containing solution (center), and the control solution for recovery (right). At left bottom, superimposed time traces obtained at the black square in the schematic drawing are illustrated for the respective images and at A-fiber stimulation. At right bottom, the spatial distributions along the dorso-ventral lines a, b and c in the schematic drawings are also illustrated. Excitation evoked by the dorsal root stimulation of A-fiber-activating strength in the normal condition is illustrated with dotted lines in the time traces and the spatial distributions. No detectable changes were observed.