Figure 4.
Anatomical sites of action of the INaP blocker riluzole and NK1R expression in the ventrolateral medulla. A, Sections showing NK1R expression (left hemisection) and microperfusion sites (right hemisection, blue circles) in the ventrolateral medulla 12.6–11.6 mm posterior to bregma. The perfusion sites were in the vicinity of the preBötC. Each perfusion site corresponds to one experiment with microperfusion in the preBötC region. B, There was a significant correlation between the latencies for riluzole to depress frequency by 10% and the distances of the perfusion sites from the preBötC (coordinates AP = −12.2, ML = 2.2, AP = −10.4) in anesthetized rats, showing that perfusion of drugs close to the preBötC has a faster effect on frequency than perfusion away from it. C, A correlation map shows that the neural site most sensitive to riluzole corresponds to NK1R expression.