[The correlation between postsynaptic inhibition and GABA, opioid peptides, SP in electroacupuncture]

Identified tract cells in lumbar enlargement were recorded from intact anaesthetized rats. The prolongation of the latency of antidromic action potential was a measure of postsynaptic inhibition. Both ST 36 and SP 6 were stimulated electrically. In EA group (N = 12) EA prolonged the latency for 0.111 +/- 0.022 ms (P < 0.001). In bicuculline group (N = 12) the prolongation of the latency for 0.010 +/- 0.004 ms (P < 0.05) by EA was less than that of EA group with statistical significance. In naloxone group (N = 12) and SP antiserum group (N = 12) EA did not induce a significant prolongation of the latency. It suggested that GABA, opioides and SP might be involved in postsynaptic inhibition induced by EA.