Figure 3.
Effect of the NK1, NK2 and NK3 receptor antagonists, RP 67580 (165 pmol), SR 48968 (165 pmol) and SR 142801 (165 pmol), respectively, on tidal volume (VT) and respiratory frequency (f) responses to microinjection of SP (33 pmol) into the cNTS of spontaneously breathing, urethane-anaesthetized rats. SP was injected into the cNTS at time zero (first arrow) and 80 min (third arrow). Ten minutes prior to the second injection of SP, vehicle (25% ethanol in normal saline) or RP 67580 (a,b), SR 48968 (c,d) or SR 142801 (e,f) were injected (second arrow). Values are the mean of four rats. Vertical lines show s.e.mean. Where error bars are not obvious, they are within the symbol.