Densitometric analysis of G(alpha o) protein subunit levels from postmortem Alzheimer disease hippocampal and prefrontal cortical membranes

An immunoblotting method using prefrontal cortical and hippocampal membrane s from control and Alzheimer disease postmortem brains was employed to dete ct three subtypes of G(alpha o) protein. In the membranes from control subj ects, the density of G(alpha o1) in hippocampus and cortex was the highest, whereas the density of G(alpha o2) Was the lowest and that of G(alpha o3) was intermediate. In the Alzheimer disease membranes from hippocampus, the density of total G(alpha o) and all three subtype forms was not changed sig nificantly when compared with control values. There were statistically sign ificant alterations in G(alpha o) in cortical membranes from Alzheimer dise ase when compared with controls. The density of G(alpha o1) was decreased b y approximately 85%, density of G(alpha o3) was decreased by approximately 95%, and total G(alpha o) density was decreased by approximately 84% of con trol value. However, G(alpha o2) density was decreased by approximately 44% but was found not to be statistically different from controls.