Effect of electroacupuncture on the long-term diazepam-induced changes in regional GABA of mammalian central nervous system.

Single electroacupuncture (EA) exposure (10 Hz, 1 volt, 15 min) to long-term (15 consecutive days) diazepam (5 mg/kg/day, i.p.) treated adult male albino rats (120-140 g) potentiated the long-term diazepam-induced increase of GABAergic activity in thalamus (Th) but the long-term diazepam-induced inhibition of GABAergic activity in cerebral cortex (CC) and spinal cord (SC) was disinhibited under similar condition of treatment. These changes in brain regional GABAergic activity may be correlated with the inhibition of single EA-induced analgesia (EAA) under similar conditions of long-term diazepam treatment with single EA exposure. Single EA exposure alone, however, inhibited GABAergic activity in Th and pons-medulla (PM) with the development of EAA. Multiple EA (10 Hz, 1 volt, 10 min/day) exposure along with long-term diazepam for 15 consecutive days inhibited GABAergic activity in CC and SC which is similar to the effect observed with either multiple EA exposure or long-term diazepam alone. But in Th the multiple EA or long-term diazepam-induced increase in GABAergic activity was significantly potentiated with the co-treatment of multiple EA and long-term diazepam for 15 consecutive days. Although GABAergic activity in PM under multiple EA or long-term diazepam treatment alone was not affected their (EA and diazepam) co-exposures under long-term conditions significantly enhanced GABAergic activity in PM. These region specific characteristic changes in central GABAergic activity under long-term treatment of diazepam along with EA may thus explain the potentiation of multiple EA or long-term diazepam-induced analgesia (tail flick latency).