title: Study of the effect of ion channel modulators on photosynthetic oxygen evolution.
abstract: Various ion channel activities can be recorded by electrophysiological methods in the outer and inner envelope membranes of chloroplasts as well as in the thylakoid membrane. However, most of these channels are poorly characterized from a pharmacological point of view. Furthermore, the molecular identity has been determined only for a few of them, preventing an understanding of their role in plant physiology. By allowing specific ion fluxes across plastidial membranes, these ion channels may either directly or indirectly regulate photosynthesis, as has been hypothesized earlier. We have determined the effect of various ion channel modulators [indole-3-acetic acid, 5-nitro-2-(3-phenylpropylamino)-benzoate, (-)-epigallocatechin-3-gallate, p-chlorophenoxyacetic acid, Konig's polyanion, Cs+, Gd3+, 4-aminopyridine, tetraethylammonium chloride, charybdotoxin, nimodipine, and cyclosporin A] on the efficiency of photosynthetic oxygen evolution in intact chloroplasts, broken chloroplasts, and isolated thylakoids. The data may improve our understanding of chloroplast ion channels and identifies inhibitors which may be exploited for electrophysiological studies.
authors.affiliation: Department of Biology, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Segalla
authors.forename: Ildiko
authors.initials: I
authors.lastname: Szabo
authors.forename: Paola
authors.initials: P
authors.lastname: Costantini
authors.forename: Giorgio Mario
authors.initials: GM
authors.lastname: Giacometti
mesh_terms: D002121:Calcium Channel Blockers / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D002586:Cesium / Q000494:pharmacology; D002736:Chloroplasts; D016572:Cyclosporine / Q000494:pharmacology; D004594:Electrophysiology; D005682:Gadolinium / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D015640:Ion Channel Gating / Q000187:drug effects; D007473:Ion Channels / Q000187:drug effects*; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology*; D018521:Plant Physiological Phenomena; D018724:Spinacia oleracea / Q000378:metabolism; D020524:Thylakoids / Q000737:chemistry / Q000187:drug effects
chemical_list: D002121:Calcium Channel Blockers; D007210:Indoleacetic Acids; D007473:Ion Channels; D002586:Cesium; C030737:indoleacetic acid; D016572:Cyclosporine; D002392:Catechin; D005682:Gadolinium; C045651:epigallocatechin gallate; D010100:Oxygen