Assessment of cannabinoid induced gene changes: tolerance and neuroprotection

The analysis of gene changes associated with exposure to cannabinoids is critical due to the multiple possible signaling pathways potentially affected by cannabinoid receptor activation. A comparison of altered gene profiles under two different conditions, one in vivo (chronic exposure to delta-9-THC) and the other in vitro (neuroprotection mediated by WIN55212-2), was made to determine whether it was possible to identify common genes that were affected. Up and down-regulated sets of genes are described. Genes affected in one or the other circumstance include alterations in a 14-3-3 regulator protein of PKC, CREB, BDNF and GABA receptor subunit proteins, as well as several genes associated with known cannabinoid receptor-coupled signaling pathways. Unexpectedly, several genes that were altered in both circumstances were associated with synaptic and membrane structure, motility and neuron growth. These included, neuronal cell adhesion molecule (NCAM), hyloronidan motility receptor, and myelin proteolipid protein. While the basis for involvement of these particular genes in cannabinoid receptor activated functional processes within the cell is still not well understood, awareness that significant numbers of genes and presumably proteins are changed following either acute or long-term exposure may provide new insight into their effects. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.