Impaired G-protein-stimulated adenylyl cyclase activity in Alzheimer's disease brain is not accompanied by reduced cyclic-AMP-dependent protein kinase A activity.
Previous studies have shown that the regulation of adenylyl cyclase activity is disrupted in Alzheimer's disease postmortem brain. In the present study, we determined whether disrupted adenylyl cyclase is accompanied by altered cAMP-dependent protein kinase activity in Alzheimer's disease superior temporal cortex and cerebellum. GTP gamma S-stimulated adenylyl cyclase activity was significantly lower in Alzheimer's disease superior temporal cortex, but not cerebellum, compared to values from a series of matched control cases. Neither basal or forskolin-stimulated adenylyl cyclase activities were significantly different between the Alzheimer's disease and control brain regions. No significant differences were seen in either particulate or soluble fraction cAMP-dependent protein kinase activities between the Alzheimer's disease and control brain regions. It is concluded that disrupted adenylyl cyclase signalling in Alzheimer's disease brain occurs specifically at the level of Gs-protein-enzyme interactions and is not accompanied by an altered cAMP-dependent protein kinase activity.
Bonkale
W L
WL
Karolinska Institute, Department of Clinical Neuroscience and Family Medicine, NOVUM, KFC, Huddinge, Sweden.
Fastbom
J
J
Wiehager
B
B
Ravid
R
R
Winblad
B
B
Cowburn
R F
RF
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology* / Q000473:pathology; D001921:Brain / Q000187:drug effects / Q000201:enzymology; D005576:Colforsin / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D012995:Solubility
D005576:Colforsin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases