This is larger than data previously reported for the modulation of the LVA by MOR activation in dorsal root ganglion neurons of the rat (≅ 35%), thalamic relay neurons (40%) and neuroblastoma cells N1E115 (≅ 20%) (Schroeder et al., 1991; Formenti et al., 1995; Yang et al., 2000). The gene discussed is OPRM1; the disease is neuroblastoma.