L- IPSCs are triggered primarily by mAChRs and reduced by endocannabinoids.

<p>A) Repeated light trains (5 Hz, 10 s, 5-ms pulses) elicited IPSC bursts (A1) that were nearly abolished by atropine (A2). A3) Group data of IPSCs in basal (Pre) conditions, and after light stimulation (Post). Values of amplitudes and frequency for all IPSCs (left and middle graphs), and frequency of large IPSCs (i.e., two s.d.s > the mean basal IPSC; right graph). B1) In atropine, light trains (10 Hz, 0.5 s) elicited small IPSC bursts (5 traces, mean in red) that were reduced by the non-selective nAChR antagonist, mecamylamine, 10 µM (B2, 2 traces, different cell than A1, A2). C1) L-IPSCs recorded in a CA1 pyramidal cell elicited by a 5 Hz, 10-s train of light pulses. DSI was induced by a 3-s voltage step (to +20 mV). C2) Control trials show IPSC bursts in the absence of DSI. C3, C4) DSI of L-IPSCs was blocked by the CB1R antagonist, AM251, 5 µM (different cell than C1, C2). C5) Group data (n = 4) of DSI in control conditions and after bath application of AM251; ^* = p<0.05; ^** = p<0.01.