Abstracts from the 18 th European Headache Congress (EHC)

Objective: In the migraine literature it has long been assumed that the meninges are impermeable in both health and disease. However, to our knowledge this has never been investigated. The Ussing Chamber is a method from the 1940"s, normally utilized to investigate membrane properties. This method was explored to investigate the barrier properties, including permeability, channel and transporter activity and receptor mediation, of the meninges from a rat.<br/><br/>Methods: Meninges from male Sprague-Dawley rats were isolated and placed in the Ussing Chamber with known polarization. Randomly and blinded to the experimenter, fluoresceine was added to either the brain-facing or the skull-facing meningeal side. Simultaneously, the Ussing Chamber was current-clamped at −5 μA allowing direct measurements of voltage changed from the different sides of the meninges to calculate the potential resistance.<br/><br/>Results: The meninges could be isolated from the rat skull and kept viable. The low resistance between the brain-facing meningeal side and the skull-facing meningeal side rendered it difficult to draw specific conclusions about ion transport across the membrane. Nevertheless, the meninges showed low permeability to fluoresceine. The investigation continues into understanding the specific layers isolated, using the current method.<br/><br/>Conclusion: This study demonstrated that while the low resistance observed between the brain-facing and skull-facing meningeal sides limits definitive conclusions regarding ion transport, the low permeability to fluorescein indicates a degree of selective barrier function in the meninges. Future work will focus on identifying the specific ion channels and transporters present in the meninges to better understand their barrier properties.