The CB1 receptor is involved in the mediation of capsaicin-induced inhibition of LA-LTP.

<p>(A) The CB1 receptor antagonist AM251 (2.5 µM) evoked a reduction of LA-LTP in comparison with controls. This reduction was not enhanced by capsaicin. In contrast, the co-administration of AM251 and capsaicin (1, 10 µM) caused an increase in the magnitude of HFS-induced LA-LTP. (B) Bar histogram of data points averaged 57 to 60 min after HFS and normalized with respect to baseline (mean ± SEM). Significant differences are indicated. *<i>p</i><0.05, **p<0.01. (C) Anandamide (1 µM, 10 µM) provoked a significant suppression of LA-LTP. Representative traces were recorded 5 min prior to tetanus (dashed lines) and 60 min after tetanus (solid lines). Data were obtained by using horizontal slices derived from adult mice.