FIGURE 7

The effect of capsazepine on blood–brain barrier disruption following experimental cerebral ischaemia–reperfusion studied in single pial venules. The permeability to sulforhodamine dye was measured immediately before, and at 5 min intervals following starch microsphere embolization. Vehicle or capsazepine (1 mol kg^-1) was injected i.v. 20 min after the embolization started. (a) In the small venular capillaries capsazepine resulted in a significantly smaller permeability increase after microsphere embolism that lasted 60 min, which showed no sign of diminishing with increased time of reperfusion (^*** P<0.0001 unpaired t-test with Welch's correction for unequal variances, eight vessels for vehicle, four vessels capsazepine, one vessel from each animal). (b) The larger venules gave a much larger permeability response, even for a shorter duration of embolism, and this too was significantly attenuated by capsazepine treatment, but the differences in the permeabilities of the two groups diminished as reperfusion progressed, until 30 min after reperfusion when there was no difference between the treated and untreated vessels (^*** P<0.0001 unpaired t-test, eight vessels for vehicle, five vessels capsazepine, one vessel from each animal).