The effects of saline gas composition and pH on haemodynamic stability in the perfused trout head preparation

The effects of saline gas composition and pH on various haemodynamic properties of the perfused trout head preparation were evaluated. Increasing the concentration of saline CO2 from a "normal" level of 0.3 (; 1 Torr = 133.322 Pa) to 5.0% resulted in a significant elevation of input pressure (Pi) and a reduction in the ratio of dorsal aortic to anterior-venous flow , whereas a reduction of pH, at constant , had only a slight effect on . Altering the of the saline from 5 to 350 Torr while maintaining water normoxic (140 Torr) was without effect on input pressure or flow distribution in the gills.