Long-term electroacupuncture (EA) treatment (10 Hz, 1 V, 10 min/day) to adult male albino rats (110 - 140 g) for 0 - 15 consecutive days gradually decreased the EA-induced analgesia from the 7th day to a very low level at the 15th day. The measurement of steady-state level of γ-aminobutyric acid (GABA) and glutamate, turnover of GABA and the activities of glutamic acid decarboxylase (GAD) and GABA-transaminase (GABA-T) in different regions of central nervous system under the above conditions of EA exposure suggest that: (i) GABAergic activity (a) increases in thalamus (Th) but decreases in ponsmedulla (PM) without any change in glutamatergic activity after 6 consecutive days of EA treatment and (b) falls in Th and spinal cord (SC) where glutamatergic activity increases following 15 consecutive days of long-term EA exposure; (ii) hypothalamic GABA system is not significantly changed after 6 or 15 consecutive days of EA treatment. Thus, these long-term EA-induced changes in GABAergic activity of Th and SC may be correlated with the EA-induced analgesia (EAA) under similar condition.