Effect of naloxone and strychnine on the presynaptic actions of Ultiva®.

<p>(A) Typical traces of miniature excitatory postsynaptic currents (mEPSCs). Ultiva® suppressed the frequency of mEPSCs (upper traces). Suppression of mEPSCs was observed in the presence of naloxone (100 μM, middle traces) but not in the presence of strychnine (10 μM, lower traces). The readings shown were obtained from same neuron (n = 6). (B) Cumulative distribution of the inter-event interval and mEPSC amplitude recorded before administration (black line) and in the presence of Ultiva® (blue line). Ultiva® did not affect the distribution of the amplitude (P = 0.27, right), but shifted the distribution to a longer inter-event interval (*P <0.001, left). (C) Summary of normalized frequencies of mEPSCs for each condition are shown (Ultiva®, n = 16; Ultiva® in the presence of naloxone, n = 13; Ultiva® in the presence of strychnine, n = 8).