Orexin signaling in recombinant neuron-like cells

To assess the role of orexin receptor signaling in neuron-like cells, Neuro-2a murine neuroblastoma and PC12 human pheochromocytoma cells were stably transfected with human OX1 or OX2 receptors. Activation of both receptors strongly elevated cellular inositol phosphates and Ca2+. A difference in the potency between orexin-A and -B was seen for OX1, but not OX2 receptors. Dependence of the orexin-mediated Ca2+ response on extracellular Ca2+ and the observed Ba2+ influx indicate that in addition to phospholipase C, orexin receptors also may couple to similar non-voltage-gated Ca2+ channels in neuronal cells as previously characterized in nonneuronal cells. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.