title: Bicuculline blocks nicotinic acetylcholine response in isolated intermediate lobe cells of the pig.
abstract: 1. The effect of bicuculline on nicotinic acetylcholine (ACh) responses in isolated intermediate lobe (IL) cells of the pig was investigated by use of patch-clamp techniques. Bicuculline was found to reduce ACh-evoked whole-cell currents (IACh) in all cells tested (n = 40). 2. The blocking effect of bicuculline on IACh was dose-dependent, the concentration producing half-maximal blockade being 43.8 microM. 3. The blockade of IACh by bicuculline was not voltage-dependent at membrane potentials above -60 mV, but a slight voltage-dependence was observed at holding potentials (HP) of -80 and -100 mV. 4. The inhibitory effect of bicuculline on IACh was partially competitive at a HP of -60 mV. 5. Neither SR 95531, a pyridazinyl gamma-aminobutyric acid derivative, nor t-butylbicyclophosphorothionate (TBPS) blocked IACh in IL cells. 6. It is concluded that bicuculline interacts directly with the ACh receptor-ionophore complex on porcine IL cells.
authors.affiliation: Institut de Physiologie (UA309 CNRS), Université Louis Pasteur, Strasbourg, France.
authors.forename: Z W
authors.initials: ZW
authors.lastname: Zhang
authors.forename: P
authors.initials: P
authors.lastname: Feltz
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018756:GABA Antagonists; D066298:In Vitro Techniques; D007539:Isonicotinic Acids / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D011724:Pyridazines / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000187:drug effects*; D012996:Solutions; D013552:Swine
chemical_list: D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018756:GABA Antagonists; D007539:Isonicotinic Acids; D011724:Pyridazines; D011978:Receptors, Nicotinic; D012996:Solutions; C037476:tert-butylbicyclophosphorothionate; C049853:gabazine; D001640:Bicuculline; C015300:isoguvacine