Fig. 3.

Circadian modulation of BDNF protein levels.A, Tissue concentrations of BDNF protein in hamster SC, V1, retina, HIPP, and CBL in the middle of the light and dark phases of the diurnal cycle. Numerals above each bar indicate the number of independent samples from which data were obtained (see Materials and Methods). B, Ratios of the mean BDNF protein concentration in the middle of the light phase of the diurnal cycle to the concentration in the middle of the dark phase.Asterisks indicate the level of statistical significance for differences between light- and dark-phase measurements inA (*p < 0.015; **p < 0.05).