CNR1 and neuroblastoma: In Chinese hamster ovary (CHO), U373 MG, and PC-3 cells, phosphatidylinositide 3-kinase activation is required for CB1 activation of ERK1/2, and the Gβγ subunit, rather than Gα, may transduce the CB1 signal.48,49 In contrast to this, ERK1/2 activation in N1E-115 mouse neuroblastoma cells, or mouse hippocampal slices, is reported to be downstream of inhibition of cyclic adenosine monophosphate (cAMP)/protein kinase A.50,51