Attenuation of Ca(2+)-induced increase in oxidative metabolism by cooling and calmodulin antagonist in mammalian brain neurons: a flow-cytometric study.
Effects of cooling and calmodulin antagonist on ionomycin-induced increase in oxidative metabolism (or formation of reactive oxygen species) of rat cerebellar neurons was examined using a flow cytometer and 2',7'-dichlorofluorescin diacetate, a fluorescent dye for intracellular hydrogen peroxide. Cooling neurons to temperatures below 16 degrees C greatly attenuated ionomycin-induced augmentation of oxidative metabolism without affecting the Ca2+ influx produced by ionomycin. Rewarming neurons to 36 degrees C in presence of ionomycin increased the oxidative metabolism, indicating a temperature-sensitive metabolic process. Substitution of Ca2+ with Ba2+ or Sr2+ completely abolished an ionomycin-induced increase in the oxidative metabolism. Pretreatment with W-7, a calmodulin antagonist, at concentrations of 10 microM or higher (up to 100 microM) produced a dose-dependent attenuation of ionomycin-induced increase in oxidative metabolism. Results suggest that calmodulin is involved in the ionomycin-induced increase in oxidative metabolism of dissociated cerebellar neurons.
Oyama
Y
Y
Laboratory of Cell Signalling--Pharmacology, Faculty of Integrated Arts and Sciences, University of Tokushima, Japan.
Chikahisa
L
L
Matoba
H
H
Furukawa
K
K
D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000037:antagonists & inhibitors*; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D003080:Cold Temperature; D005434:Flow Cytometry; D005452:Fluoresceins; D015759:Ionomycin / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D013449:Sulfonamides / Q000494:pharmacology
D002147:Calmodulin; D005452:Fluoresceins; D013449:Sulfonamides; D015759:Ionomycin; C037631:2',7'-dichlorofluorescein; C017967:W 7; D002118:Calcium