Regional distribution of guanine nucleotide binding proteins (G s and G i α) in human brain: correlation with adenylyl cyclase activity

G s and G i α immunoreactivities and adenylyl cyclase activity were measured in autopsied human brain. Highest levels of G s 52 kDa and G i α subunits occurred in frontal cortex, and highest G s 45 kDa levels in caudate. Although basal adenylyl cyclase activity was similar in all regions, GTPγS-stimulated adenylyl cyclase activity and forskolin-stimulated activity showed specific brain regional patterns which correlated with G s 45 kDa and G i α levels underscoring an important functional relationship between these measures.