Fig. 1.

BDNF-LI, SP-LI, and glutamate (GLU) were released in the dorsal horn by different patterns of afferent fiber stimulation. Basal (B), high-threshold fiber strength-stimulated (S) and recovery (R₁ andR₂) fractions were collected at a rate of 1 ml/min for 8 (A) or 3 (B,C) min. Basal values (B) represent the mean of BDNF content in three fractions collected before the stimulated fraction (S).R₂ values represent content in two fractions collected after the first recovery fraction (R₁). Dorsal root stimulation was at high-threshold fiber strength (20 V or 5 mA, 0.5 msec) and was started at the beginning of the collection of the S fraction.A, CS of the dorsal roots at low frequency (1 Hz, 480 pulses, 8 min) induced SP-LI (n = 4 slices), but not BDNF-LI (n = 4 slices) or glutamate, release (n = 4 slices). B, TS (300 pulses in 3 trains, 100 Hz) evoked the release of SP-LI (n = 6 slices) and glutamate (n= 4 slices) but not of BDNF-LI (n = 7 slices).C, BS (300 pulses in 75 trains, 100 Hz) induced release of BDNF-LI (n = 6 slices), SP-LI (n = 7 slices), and glutamate (n = 4 slices). Values (means ± SE) express concentrations in reconstituted samples. *p < 0.05 versus both B and R₂fraction values (ANOVA, followed by Tukey's test).