Neurotransmitter Gene Microarray Analysis in Human White Blood Cells and Human Stem Cells Following Morphine Exposure

Human white blood cells (WBC) and stem cells were treated with morphine and total RNA from these cells was analyzed using the Human Genome Survey microarray (Applied Biosystems). WBC nicotinic receptor gene expression, including variants, were down regulated. In general, of the 57 pre-selected neurotransmitter-related genes, only 11 changed significantly. Only 2 genes were up regulated, dopamine receptor 3 and cholinergic receptor, nicotinic, gamma polypeptide. The remaining 9 genes were down regulated, 5 in WBC and 4 in stem cells. The dopamine receptor D4 was the only gene that was commonly modulated in both cell types. It was down regulated by approx. 200% in stem cells and by 50% in WBC. The genes that exhibited the greatest extent of down regulation were 5-hydroxytryptamine receptor 3A in WBC and prepronociceptin in stem cells. Acetylcholinesterase, tyrosine hydroxylase, proenkephalin and dopamine receptor 3 were among the genes only found in WBC, whereas collagen-like tail subunit - single strand of homotrimer-of asymmetric acetylcholinesterase, dopamine receptor 1 and the serotonin transporter SLC6A4, were among those genes expressed only in stem cells. The genes for multiple sub-types of cholinergic receptors were lacking in stem cells. Thus, differential expression of genes was evident as well as specific morphine effects on gene expression, suggesting that morphine effects other neurotransmitter systems.