Assortment of GABAergic Plasticity in the Cortical Interneuron Melting Pot
Figure 3
Endocannabinoid-dependent plasticity of GABAergic synapses. (a) In cultured hippocampal neurons, eCBs mediate a form of short-term retrograde signaling strongly reducing GABAergic responses. This can be observed by the reduction of unitary inhibitory postsynaptic currents (IPSCs) evoked after a 5 sec-long depolarization (depo) of the postsynaptic neuron. The CB1R antagonist AM281 blocked the depolarization-induced suppression of inhibition (DSI). Time course of DSI is indicated in the right panel. Modified from [105]. For details, see reference [105, 106]. (b) Time course of extracellularly evoked IPSC amplitude in the CA1 area of the hippocampus. Brief depolarizations (white arrows) of the recorded pyramidal cell induce DSI (see Figure 3), whereas high-frequency stimulation (black arrow) of afferent fibers induces LTD of GABAergic responses. Traces correspond to the time points indicated by numbers in the upper graph. Both DSI and LTD induction are blocked by the selective CB1R antagonist AM251 (gray bar, lower graph). Modified with permission from [107].
