TY - JOUR
T1 - Enhancement of MTT, a tetrazolium salt, exocytosis by amyloid β- protein and chloroquine in cultured rat astrocytes
AU - Isobe, Ichiro
AU - Michikawa, Makoto
AU - Yanagisawa, Katsuhiko
N1 - Funding Information:
This study was supported by a research grant for Longevity Sciences (8A-1) and Brain Research Science from the Ministry of Health and Welfare and by CREST (Core Research for Evolutional Science and Technology), Japan. The authors thank Y. Hanai for assistance in the preparation of this manuscript.
PY - 1999/5/7
Y1 - 1999/5/7
N2 - The effect of amyloid β-protein (Aβ) on the cellular reducing activity has been a controversial issue. We determined the cellular reducing activity in cultured astrocytes using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) and 2-(2-methoxy-4-nitrophenyl)-3-(4- nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-8) reduction assays following Aβ treatment. MTT reduction was inhibited whereas WST-8 reduction was unaffected by the Aβ treatment. Furthermore, the early extracellular appearance of MTT formazan, a reduced product of MTT, was observed in association with the rapid disappearance of intracellular formazan granules. Notably, similar results were obtained in cultures treated with chloroquine, a perturbant of membrane trafficking. Our results suggest that MTT formazan exocytosis is enhanced in a similar manner by Aβ and chloroquine and that this biological activity of Aβ may underlie the pathogenesis of Alzheimer's disease.
AB - The effect of amyloid β-protein (Aβ) on the cellular reducing activity has been a controversial issue. We determined the cellular reducing activity in cultured astrocytes using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) and 2-(2-methoxy-4-nitrophenyl)-3-(4- nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-8) reduction assays following Aβ treatment. MTT reduction was inhibited whereas WST-8 reduction was unaffected by the Aβ treatment. Furthermore, the early extracellular appearance of MTT formazan, a reduced product of MTT, was observed in association with the rapid disappearance of intracellular formazan granules. Notably, similar results were obtained in cultures treated with chloroquine, a perturbant of membrane trafficking. Our results suggest that MTT formazan exocytosis is enhanced in a similar manner by Aβ and chloroquine and that this biological activity of Aβ may underlie the pathogenesis of Alzheimer's disease.
UR - http://www.scopus.com/inward/record.url?scp=0033532236&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033532236&partnerID=8YFLogxK
U2 - 10.1016/S0304-3940(99)00282-7
DO - 10.1016/S0304-3940(99)00282-7
M3 - Article
C2 - 10353344
AN - SCOPUS:0033532236
SN - 0304-3940
VL - 266
SP - 129
EP - 132
JO - Neuroscience Letters
JF - Neuroscience Letters
IS - 2
ER -