Long-lasting facilitation by dehydroevodiamine center dot HCl of synaptic responses evoked in the CA1 region of rat hippocampal slices

Abstract

We tested the effects of dehydroevodiamine . Cl (DHED) on field excitatory postsynaptic potentials (fEPSPs) evoked by the electrical stimulation of Schaffer collaterals-commissural fibres in the CAI region of rat hippocampal slices. Bath applications of 10 muM DHED for 20 or 40 min induced long-lasting facilitation of fEPSPs, which outlasted the presence of DHED. A 10 min treatment with a higher concentration (100 muM) also induced long-lasting facilitation. The long-lasting facilitation was blocked either by 10 muM atropine, the muscarinic receptor antagonist, or by 50 muM D-2-amino-5-phosphonopentanoic acid (D-AP5), an NMDA receptor antagonist. These results show that DHED produces long-lasting facilitation of synaptic transmission, and that this facilitation depends upon the activation of both the muscarinic and NMDA receptors.