title: Metal cations as synaptosomal calcium blockers in studies with Fura-2.
abstract: Metal ions are often used to block calcium channels in various tissues, including synaptosomes. In the present study, Fura-2 was used to determine the effectiveness of various metal ions as calcium channel blockers in rat brain synaptosomes in vitro. In buffer solutions, La3+ and Cd2+ increased the Fura-2 fluorescence in a manner similar to Ca2+. Ni2+ and Mn2+ appeared to be fluorescence quenching cations, and Sr2+ and Co2+ had little effect on the fluorescence of Fura-2. In suspensions of synaptosomes under resting conditions, Cd2+, Ni2+ and Mn2+ were found to be not suitable for use in synaptosome studies. On the other hand, La3+ and Co2+ had little effect on the Fura-2 fluorescence of resting synaptosomes, and under depolarizing conditions, La3+ and Co2+ decreased the Fura-2 fluorescence. These results, therefore, suggest that La3+ and Co2+ may be suitable as calcium channel blockers in synaptosome studies.
authors.affiliation: Dept. of Physiology, University of Alberta Faculty of Medicine, Edmonton.
authors.forename: Y D
authors.initials: YD
authors.lastname: Sun
authors.forename: C G
authors.initials: CG
authors.lastname: Benishin
mesh_terms: D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000493:pharmacokinetics*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D005456:Fluorescent Dyes; D016257:Fura-2; D008670:Metals / Q000494:pharmacology*; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D001572:Benzofurans; D002121:Calcium Channel Blockers; D002413:Cations, Divalent; D005456:Fluorescent Dyes; D008670:Metals; D002118:Calcium; D016257:Fura-2