RECEPTOR MEDIATION IN CANNABINOID STIMULATED ARACHIDONIC-ACID MOBILIZATION AND ANANDAMIDE SYNTHESIS

Numerous reports have suggested that increased synthesis of eicosanoid s is a significant effect of cannabinoids in several models including the human. To address the question of receptor mediation in this proce ss we have carried out experiments using oligonucleotides that are ant isense to the CB1 and to the CB2 receptors. We have synthesized sense, antisense and random oligonucleotide probes to test for receptor invo lvement in THC stimulation of arachidonic acid release in three cell l ines of both central and peripheral origin. Treatment of N18 mouse neu roblastoma cells with the CB1 antisense probe, at two concentrations, resulted in a dramatic decrease of THC stimulated arachidonate release while treatment with antisense CB2 was less effective. Synthesis of t he novel eicosanoid, anandamide, was also reduced by antisense CB1 but not by antisense CB2. Western blot analysis indicated a decreased lev el of CB1 in CB1 antisense treated cells. The CB1 antagonist, SR141716 A, was effective in reducing the THC elevated levels of free arachidon ate in these cells in agreement with the antisense data. In the macrop hage line, RAW 264.7, we found that while the sense, the random and th e CB1 antisense oligonucleotides were ineffective, the CB2 antisense p robe gave significant reductions of the THC induced response. The CB2 probe was also effective in reducing the release of arachidonate in WI -38 human lung fibroblasts. These findings support the idea of a recep tor mediated process for cannabinoid stimulation of eicosanoid synthes is.