Pr. Lowenstein et al., IMMUNOLOCALIZATION OF PROTEIN PHOSPHATASE INHIBITOR-1 IN THE CEREBRAL-CORTEX OF THE RAT, CAT AND FERRET, Brain research, 676(1), 1995, pp. 80-92
The distribution of inhibitor-1 was analysed in the neocortex of cat,
ferret and rat by immunocytochemistry (at the light and electron micro
scope levels) and by immunoblotting using an affinity purified antibod
y which recognises both the phosphorylated and dephosphorylated forms
of the protein. In each mammalian cortex immunocytochemical techniques
identified inhibitor-1 predominantly in infragranular pyramidal neuro
ns and, at a lower concentration, in supragranular pyramidal neurons o
f cortical layers II-III, and V-VI. Within the cortical layers, neuron
al cell bodies and apical dendrites were stained strongly but no immun
oreactivity was associated with dendritic spines. Regional differences
in intensity of staining were revealed when appropriate antibody conc
entrations were used; the concentration of inhibitor-1 appeared to fol
low a gradient with the highest levels in layer VI and the lowest in l
ayer I. The results were confirmed by immunoblotting of microdissected
cortical regions which identified the inhibitor-1 protein unambiguous
ly. The distribution of inhibitor-1 is different from that reported by
other investigators.