The Effects of GABA-receptor Antagonists on the Spinal Cord Stimulation-induced Antinociception in Cats / 대한마취과학회지

ABSTRACT

BACKGROUND: Spinal cord stimulation (SCS) is a clinical off spring of the gate-control theory and known as an effective treatment for pain from a neurogenic origin. The prolonged pain relief following a short stimulation period is believed to be related with the GABAergic system. The aims of this study were to see if the SCS, similar to that being used in clinical condition, suppressed the nociceptive transmission in the spinal dorsal horn, and if so, which type of GABA receptor may be involved in the antinociceptive process. METHODS: The cord dorsum potential (CDP) was recorded at the dorsal root entry zone of the lumbosacral enlargement for a long time period (60 min) in response to electrical stimulation of the dorsal root, respectively, after SCS in anesthetized cats. CDP was recorded after intrathecal application of bicuculline (GABA (A) receptor antagonist) and phaclofen (GABA (B) receptor antagonist) and 20 min after SCS that followed the intrathecal application of bicuculline or phaclofen. Asigma- and C-fiber wave responses were differentiated according to the conduction velocity. RESULTS: The C-fiber wave decreased significantly after SCS but the Asigma-fiber wave did not on the CDP. After intrathecal administration of bicuculline, the Asigma- and C-fiber waves increased significantly and bicuculline also prevented a SCS-induced reduction of the C-fiber wave. Phaclofen did not change the amplitude of Asigma- and C-fiber wave. When the phaclofen was administered intrathecally, SCS did not decrease the amplitude of the Asigma- and C-fiber waves. CONCLUSIONS: In conclusion, the present results indicate that SCS suppresses C-fiber transmission of acute nociceptive electrical stimuli and both GABA (A) and (B) receptors mediate the long-lasting antinociceptive effect of SCS.