1-BCP, A MEMORY-ENHANCING AGENT, SELECTIVELY POTENTIATES AMPA-INDUCED [H-3] NOREPINEPHRINE RELEASE IN RAT HIPPOCAMPAL SLICES

It is now clear that the AMPA subtype of ionotropic glutamate receptors (iGluRs) undergoes a rapid desensitization in response to activation by AMPA receptor agonists. This desensitization is inhibited by compounds such as aniracetam and cyclothiazide, which act at a distinct site on the AMPA receptor complex. In particular, cyclothiazide greatly potentiates AMPA receptor-mediated depolarizing responses in the hippocampus. We have recently shown cyclothiazide also increases AMPA-induced release of [H-3]norepinephrine ([H-3]NE). More, recently, a benzamide compound, 1-(1,3-benzodioxol-5-ylcarbonyl)-piperidine (1-BCP), has been reported to enhance AMPA-induced currents and to facilitate memory retention in rats in a number of memory tasks. In this study, the effects of 1-BCP on excitatory amino acid agonist-induced [H-3]NE release in rat hippocampal slices were determined. We report that 1-BCP, like cyclothiazide, selectively potentiates AMPA-induced [H-3]NE release. However, cyclothiazide was more potent and efficacious than 1-BCP. Nevertheless, these data suggest a role for AMPA receptor-mediated enhancement of norepinephrine release as a mechanism of action for nootropic compounds such as 1-BCP.