The effect of CB1 receptor activation on glutamatergic transmission in the BLA has also been extensively studied. When recording from neurons in the LA, and stimulating glutamatergic afferents arising from the EC, Win 55212-2 reduced AMPA-dependent eEPSC amplitude to 52% of control while significantly increasing the PPR, an effect absent in CB1−/− mice. Win 55212-2 also reduced the frequency of sEPSCs and action potential-independent mEPSCs without affecting the amplitude of either response. These data indicate that CB1 receptor activation decreases EC-evoked excitatory glutamatergic transmission onto LA principal neurons via a presynaptic mechanism (Azad et al., 2003). This effect was subsequently confirmed to be CB1 receptor-dependent using mutant mice with selective deletion of CB1 receptors from forebrain glutamatergic neurons (Domenici et al., 2006).
