title: The rostral migratory stream plays a key role in intranasal delivery of drugs into the CNS.
abstract: BACKGROUND
  The blood brain barrier (BBB) is impermeable to most drugs, impeding the establishment of novel neuroprotective therapies and strategies for many neurological diseases. Intranasal administration offers an alternative path for efficient drug delivery into the CNS. So far, the anatomical structures discussed to be involved in the transport of intranasally administered drugs into the CNS include the trigeminal nerve, olfactory nerve and the rostral migratory stream (RMS), but the relative contributions are debated.
  
  
  RESULTS
  In the present study we demonstrate that surgical transection, and the resulting structural disruption of the RMS, in mice effectively obstructs the uptake of intranasally administered radioligands into the CNS. Furthermore, using a fluorescent cell tracer, we demonstrate that intranasal administration in mice allows agents to be distributed throughout the entire brain, including olfactory bulb, hippocampus, cortex and cerebellum.
  
  
  CONCLUSIONS
  This study provides evidence of the vital role the RMS has in the CNS delivery of intranasally administered agents. The identification of the RMS as the major access path for intranasally administered drugs into the CNS may contribute to the development of treatments that are tailored for efficient transport within this structure. Research into the RMS needs to continue to elucidate its limitations, capabilities, mechanisms of transport and potential hazards before we are able to advance this technique into human research.
authors.affiliation: University of Texas Health Science Center San Antonio, San Antonio, Texas, United States of America.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Scranton
authors.forename: Lauren
authors.initials: L
authors.lastname: Fletcher
authors.forename: Shane
authors.initials: S
authors.lastname: Sprague
authors.forename: David F
authors.initials: DF
authors.lastname: Jimenez
authors.forename: Murat
authors.initials: M
authors.lastname: Digicaylioglu
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D001812:Blood-Brain Barrier; D002490:Central Nervous System / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL