Cannabinoids reduce synaptic transmission through presynaptic
mechanisms. (A) The CB1 agonist WIN-2 (5 μM) reduces the
frequency of sEPSCs from 4.1 ± 1.1 Hz to 1.4 ± 0.3 Hz
(n = 12; P < 0.05). A representative pair of
traces and the bar diagram (n = 12) are shown. The
amplitudes of the sEPSCs are unaffected by WIN-2, as seen in the bars
(control, 8.5 ± 0.12 pA; WIN-2, 8.2 ± 0.04 pA; n = 12;
P > 0.05) and one representative example of the cumulative
probability of sEPSC amplitudes. (B) Application of WIN-2 (5
μM) also reduces the frequency of mEPSCs recorded in the presence of
1 μM TTX (control, 4.5 ± 0.9 Hz; WIN-2, 2 ± 0.7 Hz;
n = 6; P < 0.05). A representative pair of
traces and the bar diagram are shown. WIN-2 (5 μM) does not alter
mean mEPSC amplitude as seen in the bars (control, 6.6 ± 0.8 pA;
WIN-2, 6.6 ± 1.1 pA; n = 6; P > 0.05) and one
representative example of the cumulative probability of mEPSC
amplitudes.