[Effect of the Ca ionophore A-23187 on the plasmatic and mitochondrial potentials of the brain synaptosomes in rats: fluorescence measurements].
The applicability of the potential-sensitive dye diS-C3-(5) for the study of A23187 + Ca2+ induced plasma membrane hyperpolarization was tested in rat brain synaptosomes. An appropriate dye synaptosome ratio was chosen for the fluorescence titration dye in Ca-free Krebs-Ringer solution. The fluorescence intensity of the probe was increased upon the addition of Ca2+ (1 microM) to the synaptosomes in the presence of A23187 (1 microM). The effect of Ca2+ + A23187 persisted in a Na+-free medium or when Na+ channels were inhibited by tetrodotoxin as well as in high K+-depolarized synaptosomes (75 microM KCl). In the presence of oligomycin or a protonophore (1 microM) the effect of Ca2+ + A23187 was suppressed. This suggests that the A23187-induced fluorescence increase is due to a depolarization of intrasynaptosomal mitochondria. Therefore, the use of the dye diS-C3-(5) for the study of Ca-induced hyperpolarization does not seem to be feasible unless a quantitative model of changes in fluorescence related to the plasma and mitochondrial membrane potentials is elaborated.
Tiniakova
L R
LR
Antonikov
I M
IM
Glebov
R N
RN
D000818:Animals; D052160:Benzothiazoles; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002232:Carbocyanines; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology; D051381:Rats; D013050:Spectrometry, Fluorescence; D013574:Synaptosomes / Q000187:drug effects* / Q000502:physiology
D052160:Benzothiazoles; D015220:Calcium Channels; D002232:Carbocyanines; D005456:Fluorescent Dyes; D000001:Calcimycin; C012944:3,3'-dipropyl-2,2'-thiadicarbocyanine; D002118:Calcium
Vliianie Ca-ionofora A23187 na plazmaticheskiĭ i mitokhondrial'nyĭ potentsialy sinaptosom mozga krys: fliuorestsentnye izmereniia.