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SYSTEMIC ADMINISTRATION OF KAINIC ACID INCREASES GABA LEVELS IN PERFUSATE FROM THE HIPPOCAMPUS OF RATS IN VIVO
Citation:
Zhang, W., B. Rogers, P. Tandon, P. Hudson, T. Sobotka, J. Hong, AND H. Tilson. SYSTEMIC ADMINISTRATION OF KAINIC ACID INCREASES GABA LEVELS IN PERFUSATE FROM THE HIPPOCAMPUS OF RATS IN VIVO. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-90/522 (NTIS PB91211391).
Description:
The ventral hippocampi of male, Fischer-344 rats were implanted with microdialysis probes and the effects of systemically administered kainic acid (KA) (8 mg/kg, s.c.) on the in vivo release of amino acids were measured for four hours after administration. n order to measure GABA release in vivo, gamma- vinyl-GABA (GVG), an irreversible inhibitor of GABA transaminase, was injected intrahippocampally prior to perfusion. VG pretreatment resulted immeasurable levels of GABA in the perfusate without significant effects on the release of aspartate, glutamate, glutamine, glycine or taurine. ollowing GVG pretreatment systemic administration of produced a time-dependent increase in GABA, as well as all other amino acids except glutamine, which was initially decreased. hese results show for the first time that systemically administered increases extracellular GABA levels, an effect previously reported only in vitro. hese data suggest that prior to destruction of GABA-containing interneurons in the hippocampus, there is an increased activity of those GABA interneurons reflected as an increase in extracellular GABA levels.