Homologous and heterologous desensitization of 15d-PGJ
vs. AITC. Multi-dose experiments 15d-PGJ2 (A) or AITC (B) cause homologous or heterologous desensitization in vivo, we performed multi-dose experiments. The inter-stimulus interval was 1 h. Pre-injection (10 μL ipl.) of vehicle was used as control. Behavior was recorded at 10-min intervals for 30–40 min. (A) Nocifensive response to 15 mM 15d-PGJ2 or 50 mM AITC after 15 mM 15d-PGJ2 pre-injection was significantly reduced relative to vehicle pre-injected. (Not shown for Figure clarity: *p < 0.05 for 15 mM 15d-PGJ2/15d-PGJ2 vs. 15d-PGJ2/vehicle at 10 and 20 min time points; **p < 0.01 for 15d-PGJ2/AITC vs. vehicle/AITC at 10 min time point (B) Nocifensive responses to the injection of either 15 mM AITC or 15d-PGJ2 were not reduced by 15 mM AITC pre-injection relative to vehicle controls. (n = 8 animals per group; Values expressed as mean ± SEM). Data were analyzed using RMANOVA with Bonferonni post-hoc comparisons.