Synaptic vesicle-bound phospholipase(s) acting on phosphatidylinositol exhibit(s) high susceptibility to brain ischemia.
The activity of phospholipase C acting against [3H]-inositol-phosphatidylinositol (PI) and the activity of arachidonic acid (AA) release from [1-14C]arachidonoyl-phosphatidylinositol by enzyme(s) located in synaptic vesicles (SV) isolated from normoxic and ischemic brains was investigated. Brain ischemia significantly activated phospholipase C (PhLC) by about 90% and AA release by about 50%. PhLC and AA release in SV isolated from brain submitted to ischemia were not further activated by 2 mM CaCl2 contrary to the enzymes from normoxic brain. The activation of PhLC and PhLA2 may produce conformational changes and rearrangement of the SV membranes leading to vesicle-membrane fusion and subsequently to massive neurotransmitter release known to occur during ischemia.
Strosznajder
J
J
Department of Neurochemistry, Polish Academy of Sciences, Warsaw.
Goracci
G
G
Gaiti
A
A
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D002545:Brain Ischemia / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D005849:Gerbillinae; D010716:Phosphatidylinositols / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000378:metabolism*; D010738:Type C Phospholipases / Q000494:pharmacology*
D001095:Arachidonic Acids; D010716:Phosphatidylinositols; D016718:Arachidonic Acid; D010738:Type C Phospholipases; D002118:Calcium