Rapid generation of 2-arachidonoylglycerol, an endogenous cannabinoid receptor ligand, in rat brain after decapitation

Rat brain, frozen in liquid nitrogen immediately after decapitation, contai ns a substantial amount of 2-arachidonoylglycerol (0.34 nmol/g tissue), an endogenous cannabinoid receptor ligand. The level of 2-arachidonoylglycerol in the brain was rapidly augmented after decapitation, the peak being note d 30 s after decapitation (1.54 nmol/g tissue). Noticeably, there are two p hases during the increase in the levels of 2-arachidonoylglycerol: a rapid transient increase and a subsequent gradual sustained increase, suggesting that at least two separate mechanisms are involved in the generation of 2-a rachidonoylglycerol in the decapitated brain. Gradual sustained formation w as also observed for other monoacylglycerols, (e,g, 2-paimitoylglycerol plu s 2-oleoylglycerol and 2-cis-vaccenoylglycerol). Thus, it is important to m inimize post-mortem changes to estimate the exact tissue levels of 2-arachi donoylglycerol as well as other monoacylglycerols in the brain. (C) 2001 El sevier Science Ireland Ltd. All rights reserved.