Fig. 6.

Depression of sIPSCs by activation of μ opioid receptors. A, sIPSCs in a single GP neuron recorded at a holding potential of −50 mV in the presence of CNQX (10 μm) and dl-AP-5 (100 μm). Bath application of met-enkephalin (30 μm) suppressed the frequency and amplitude of sIPSCs. This effect was replicated by the μ opioid receptor agonist DAMGO (1 μm), whereas the δ opioid receptor agonist DPDPE (1 μm) was without effect. sIPSCs were blocked by TTX (1 μm). B, Cumulative frequency distributions of sIPSCs before and after the addition of met-enkephalin (p < 0.05) (i), DAMGO (p < 0.05) (ii), and DPDPE (non significant) (iii). Data were collected over a period of 120 sec. Same cell asA.