The electrogenesis of adrenaline-hyperpolarization of sympathetic ganglion cells in bullfrogs.
Bullfrog sympathetic ganglion cells produced hyperpolarizing (Ad-hyperpolarization) and depolarizing (Ad-depolarization) responses when adrenaline (Ad) was directly applied to ganglia. The nature of Ad-hyperpolarization recorded by the sucrose-gap method was analysed in the present experiment, in order to clarify its electrogenesis. The amplitude of Ad-hyperpolarization was increased or decreased while ganglion cell membranes were hyperpolarized or depolarized, respectively, by applying a moderate conditioning current to the ganglia. The Ad-hyperpolarization was depressed in K+-rich solutions as well as in K+-deficient solutions. It was not significantly altered by replacing the extracellular total Cl ions by equimolar glutamate or thiosulfate ions. Ad-hyperpolarization was depressed and finally abolished in the Na+-free Tris solution, and was reversibly eliminated in the solution where Na ions were totally replaced by equimolar Li ions. It was enhanced when a preparation was previously perfused in the K+-free, Na+-rich solution for certain periods, during which the intracellular Na+ concentration might be increased. Ad-hyperpolarization was depressed by lowering the temperature and by the action of ouabain, and the amplitude of Ad-hyperpolarization was markedly increased in the presence of TEA. The ionic mechanism underlying the generation of Ad-hyperpolarization was discussed on the basis of these present experimental results, and it was suggested that Ad-hyperpolarization might be generated by an electrogenic sodium pump.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology*; D005725:Ganglia, Autonomic / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects*; D009539:Nicotinic Acids / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D010643:Phenoxybenzamine / Q000494:pharmacology; D011892:Rana catesbeiana; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D009539:Nicotinic Acids; D013757:Tetraethylammonium Compounds; D010643:Phenoxybenzamine; D010042:Ouabain; D001285:Atropine; D007545:Isoproterenol; D000109:Acetylcholine; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine