title: Effect of endothelin-1 on the excitability of rat cortical and hippocampal slices in vitro.
abstract: Endothelin-1 (ET-1) is a neuroactive protein produced in most brain cell types and participates in regulation of cerebral blood flow and blood pressure. In addition to its vascular effects, ET-1 affects synaptic and nonsynaptic neuronal and glial functions. Direct application of ET-1 to the hippocampus of immature rats results in cerebral ischemia, acute seizures, and epileptogenesis. Here, we investigated whether ET-1 itself modifies the excitability of hippocampal and cortical circuitry and whether acute seizures observed in vivo are due to nonvascular actions of ET-1. We used acute hippocampal and cortical slices that were preincubated with ET-1 (20 μM) for electrophysiological recordings. None of the slices preincubated with ET-1 exhibited spontaneous epileptic activity. The slope of the stimulus intensity-evoked response (input-output) curve and shape of the evoked response did not differ between ET-1-pretreated and control groups, suggesting no changes in excitability after ET-1 treatment. The threshold for eliciting an evoked response was not significantly increased in either hippocampal or cortical regions when pretreated with ET-1. Our data suggest that acute seizures after intrahippocampal application of ET-1 in rats are likely caused by ischemia rather than by a direct action of ET-1 on brain tissue.
authors.affiliation: Department of Developmental Epileptology, Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: R
authors.initials: R
authors.lastname: Konopková
authors.forename: I
authors.initials: I
authors.lastname: Vilagi
authors.forename: S
authors.initials: S
authors.lastname: Borbely
authors.forename: H
authors.initials: H
authors.lastname: Kubová
authors.forename: J
authors.initials: J
authors.lastname: Otáhal
mesh_terms: D000818:Animals; D019332:Endothelin-1 / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
chemical_list: D019332:Endothelin-1