In conclusion, we observed that [51Cr]-EDTA does not pass to the CNS in a major way. However, [51Cr]-EDTA readily passed the TG by >30 times compared to the CNS. Application of CFA or IS (studied at 2, 24 or 48 h after the application) did not show altered transfer constant to [51Cr]-EDTA. Thus, with these experiments we suggest; (i) dural triggered TG inflammation, with IS or CFA does not change BBB passage, and (ii) the TG is readily exposed to circulating molecules and could provide a site where anti-migraine drugs could interact with the trigeminal system.