Regional distribution of phosphoinositide-specific phospholipase C activity in rat brain.
The phosphatidylinositol (PI) and phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolytic activities of phosphoinositide-specific phospholipase C (PLC) were measured in membrane and cytosol fractions from 7 discrete areas of the rat brain. Both the PI-PLC and PIP2-PLC specific activities were found to differ significantly among the 7 discrete brain areas. In the membrane fraction, the PIP2-PLC activity was higher than that of PI-PLC in each region, suggesting that the PLC in membranes prefers PIP2 to PI as substrate. The PIP2-PLC activities in the membrane were high in prefrontal cortex and cerebellum, but rather low in medulla oblongata and hypothalamus. The PI-PLC specific activity in the cytosol was significantly higher than that in the membrane of all brain areas examined. The PI-PLC specific activity in membranes is inversely proportional to its activity in the cytosol. In the cytosol fraction, the distribution pattern of PI-PLC specific activity resembled that of PIP2-PLC. These results indicate that PLCs are differently distributed in various regions of rat brain, and suggest the regional differences in neuronal transduction.
Nishida
A
A
Department of Neurology and Psychiatry, Gifu University School of Medicine, Japan.
Kaiya
H
H
Tohmatsu
T
T
Banno
Y
Y
Wakabayashi
S
S
Nozawa
Y
Y
D000818:Animals; D001921:Brain / Q000201:enzymology*; D001923:Brain Chemistry; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D008297:Male; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000378:metabolism; D010738:Type C Phospholipases / Q000032:analysis*
D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D010738:Type C Phospholipases