Phospholipase A2 activity in rat embryonic brain and in primary cultures of cortical neurons

Summary.

We investigated, with the aid of a radio-enzymatic method, the developmental changes in the activity of 85 kDa calcium-dependent cytosolic phospholipase A₂ (cPLA₂) in pre-term embryonic rat brain and in primary cultures of cortical neurons. PLA₂ activity was highest in the brains of 18 day embryos (E18) and gradually decreased toward birth (E18 through E21). No significant differences were found regarding cPLA₂ activity in different topographies, namely hippocampus, cortex, and total brain. In primary cultures of E18/E19 cortical neurons, cPLA₂ activity was higher than the respective embryonic tissue activity, straight from early development. In vitro cPLA₂ activity peaked on the 4^th day in culture, and decreased after the six days of incubation, when the cultures became mature. This result reinforces previous evidence that cPLA₂ plays an important role in the early development of the nervous system, and further suggests that it may be implicated in neurodevelopmental processes and in in vitro neuronal survival. We believe that we have produced a useful model for the tissue culture study of PLA₂ metabolism and biochemistry, which can be further addressed to the investigation of the biology of neurodegenerative and neuropsychiatric disorders.