(+/-)3,4-Methylenedioxyamphetamine inhibits the TEA-sensitive K+ current in the hippocampal neuron and the Kv2.1 current expressed in H1355 cells

The whole-cell patch clamp method was used to study the effects of (+/-)3,4-methylenedioxyamphetamine (MDA) in hippocampal CM neurons from neonatal rats and in lung epithelial H1355 cells expressing Kv2.1. Extracellular application of MDA (30 mu M) induced bursts of action potentials in hippocampal CA1 neurons exhibiting single spike action potentials without a bursting firing pattern, and promoted action potential bursts in hippocampal CA1 neurons exhibiting bursting firing of action potentials. Whereas MDA (30 and 100 mu M) markedly decreased the delayed outward current in hippocampal CM neurons, MDA (100 mu M) only slightly decreased the fast-inactivating K+ current (I-A) current. Furthermore, MDA (100 mu M) substantially decreased the delayed outward current in the presence of 4-aminopyridine (4-AP; 3 mM), but did not significantly decrease the delayed outward current in the presence of tetraethylammonium (TEA; 30 mM). MDA (100 mu M) also inhibited the current in H1355 cells expressing Kv2.1. Our results have shown that MDA inhibits the TEA-sensitive K+ current in the hippocampus and the Kv2.1 current expressed in H1355 cells. These effects may contribute to the pharmacological and toxicological effects of MDA. (C) 2014 Published by Elsevier Ltd