Figure 7.

Involvement of endocannabinoids and calcineurin in het-LTD induced at different pathways. A, Hom-LTP of UL-evoked EPSPs (top) were induced, but het-LTD of WM-evoked EPSPs (bottom) was not induced by TBS of the UL site during the application of a CB₁R antagonist, AM251 (filled circles). In the control condition without AM251, het-LTD of WM-evoked EPSPs was induced (open circles). The number of cells analyzed is indicated in parentheses at top left. B, Hom-LTP of WM-evoked EPSPs (top) and het-LTD of UL-evoked EPSPs (bottom) were induced by TBS of the WM site with (filled circles) and without (open circles) AM251. Other conventions are the same as in A. C, Induction of hom-LTP and absence of het-LTD in CB₁R-KO mice. Top, Hom-LTP of UL-evoked EPSPs was induced by TBS of the UL site in CB₁R-KO mice (filled circles) and wild-type mice (open circles). Bottom, Het-LTD was not induced in CB₁R-KO mice (filled circles), but induced in wild-type mice (open circles). D, Involvement of calcineurin in WM-induced het-LTD of UL-evoked EPSPs. Hom-LTP of WM-evoked EPSPs was induced by TBS of the WM site with (filled circles) and without (open circles) a calcineurin inhibitor, FK-506 (top). Het-LTD of UL-evoked EPSPs was not induced by TBS of the WM site during the application of FK-506 (bottom, filled circles). In the normal condition without FK-506, het-LTD was induced (open circles).