Fig. 5. IP₃ gated internal stores do not contribute to CBF excitation pathway. (A) CBF excitation caused by 100 µmol l^-1 dopamine (DA) in CBF explants either bathed in FSW (open squares, N=5) or SW including 1 µmol l^-1 of the IP₃ inhibitor xestospongin C (Xesto; filled circles, N=5). (B) Comparisons of percent change in CBF with and without 1 µmol l^-1 xestospongin C show it has no effect on dopamine or TPep-NLS (TPep) induced CBF excitation. 100 µmol l^-1 Dopamine (N=5, P0.27) and 10 µmol l^-1 TPep-NLS (N=5, P0.06) induced CBF excitation in a bath containing 1 µmol l^-1 xestospongin C was indistinguishable from excitation induced by either alone.