title: Activation by cromakalim of pre- and post-synaptic ATP-sensitive K+ channels in substantia nigra.
abstract: Membrane potentials and synaptic potentials were recorded using the patch clamp technique from neurons isolated from the substantia nigra. Intracellular perfusion of dopaminergic neurons with an ATP-free solution caused hyperpolarization and inhibition of firing. Intracellular perfusion with a solution containing 2 mM ATP prevented this hyperpolarization, but application of the K+ channel openers cromakalim and pinacidil caused a similar hyperpolarization as well as the disappearance of bicuculline-sensitive synaptic potentials. All these effects were reversed by sulfonylureas, indicating that they are mediated by ATP-sensitive K+ channels. It is concluded that K+ channel openers activate ATP-sensitive K+ channels both presynaptically on GABAergic terminals and postsynaptically on substantia nigra dopaminergic neurons.
authors.affiliation: Institut de Pharmacologie Moléculaire et Cellulaire du CNRS, UPR 411, Valbonne, France.
authors.forename: M A
authors.initials: MA
authors.lastname: Häusser
authors.forename: J R
authors.initials: JR
authors.lastname: de Weille
authors.forename: M
authors.initials: M
authors.lastname: Lazdunski
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology*; D001640:Bicuculline / Q000494:pharmacology; D019806:Cromakalim; D005905:Glyburide / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010276:Parasympatholytics / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
chemical_list: D001578:Benzopyrans; D010276:Parasympatholytics; D015221:Potassium Channels; D011758:Pyrroles; D019806:Cromakalim; D000255:Adenosine Triphosphate; D005905:Glyburide; D001640:Bicuculline