ADP-ribosylation factor (Arf)-related protein 1 (ARFRP1) is a membrane-associated GTPase, which inhibits the Arf/Sec7-dependent activation of phospholipase D and belongs to the Arf-like (Arl) GTPases. Although ARFRP1 is involved in post-Golgi membrane trafficking and its lack leads to embryonic lethality, little is known about its possible function in the central nervous system. To obtain more knowledge about ARFRP1, we have characterized its mRNA distribution in adult mouse brain by in situ hybridization and real-time PCR. We observed a widespread distribution of ARFRP1-mRNA, with the highest levels in cerebral cortex, thalamic nuclei, colliculus, substantia nigra and granule cell layer of cerebellum. Moderate levels were observed in some amygdaloid nuclei, CA2 area and dentate gyrus of hippocampus, endopiriform nuclei, globus pallidus, striatum, molecular layer of cerebellum, and locus coeruleus, whereas no expression was detected in hypothalamic nuclei, CA1 and CA3 areas of hippocampus, zona incerta. A significant decrease of ARFRP1-mRNA was observed in cerebral cortex following sleep deprivation, whereas no change was observed in cerebellar cortex, locus courelus, brainstem, hippocampus and pontine nuclei. This study provides the first detailed analysis of the regional distribution of ARFRP1 in the mouse brain and a quantitative view of its changes following sleep deprivation.