Effects of pulsatile perfusion on flow distribution within an isolated saline-perfused trout head preparation

Abstract

Increasing the input pulse pressure to the gills of an isolated, saline-perfused trout head preparation significantly increased the anterior venous–venolymphatic flow returning to the heart. This increased flow could have been brought about by the mechanical interaction between afferent–efferent vessel pulse pressures being transmitted to the low pressure venolymphatic system. Alternatively, these pressure pulses may have increased lymphatic drainage from the gill tissues. Changes in perfusate oxygen tension across these gills were consistent with data from other saline-perfused preparations, but were not comparable to in vivo data from Salmo gairdneri. The measured values for gill resistance and general head circulation resistance to flow were similar to other saline-perfused preparations, but again were not comparable to in vivo data. The possible roles of increased venolymphatic flow to gill function were discussed.