Accurate evaluation of 1,2-diacylglycerol in gerbil forebrain using HPLC and in situ freezing technique.

Gerbil forebrains were frozen in situ to inactivate the tissues, and 1,2-diacylglycerols were first measured quantitatively by HPLC. Although 1,2-diacylglycerols were completely recovered from the HPLC column, the control amount of 1,2-diacylglycerol in gerbil forebrain was only 79.6 nmol/g wet weight, which is about one-fourth of that previously reported for gerbil brain inactivated by liquid N2 after decapitation instead of in situ freezing. The fatty acid composition of 1,2-diacylglycerols in gerbil forebrain was first reported and the control 1,2-diacylglycerols were richer in palmitic acid than in stearic acid or arachidonic acid, which is rather different from the data previously reported for mouse or rat brain obtained by decapitation and analyzed by traditional TLC methods. The amount of 1,2-diacylglycerol increased by 82.9% in gerbil forebrain during 5 min of ischemia induced by bilateral carotid ligation. Arachidonic acid and stearic acid were abundant in the 1,2-diacylglycerols produced by 5 min of ischemia. Thus we were able to obtain accurate values of the amount and the fatty acid composition of 1,2-diacylglycerols in gerbil forebrains using HPLC and in situ freezing technique.