REDUCED NITRIC-OXIDE RESPONSIVE SOLUBLE GUANYLYL CYCLASE ACTIVITY IN THE SUPERIOR TEMPORAL CORTEX OF PATIENTS WITH ALZHEIMERS-DISEASE

Particulate and soluble guanylyl cyclase activities were studied in postmortem temporal cortex from a series of Alzheimer's disease patients and matched control subjects. Particulate guanylyl cyclase activity was not significantly different between groups. In contrast, the V-max values for basal and sodium nitroprusside-stimulated soluble guanylyl cyclase activities were approximately 50% lower in the Alzheimer's disease cases, compared to controls. This difference between groups was statistically significant for sodium nitroprusside-stimulated, but not for the basal, enzyme activities. These results provide the first evidence for a loss of nitric oxide responsive guanylyl cyclase activity in Alzheimer's disease brain.