CHANGES IN THE PATTERNS OF IN VITRO RESPIRATION OF KITTEN DIAPHRAGMS DURING THE FIRST FEW WEEKS AFTER BIRTH

Abstract

The pattern of respiration in vitro of hemidiaphragms from cats aged 1 to 42 days was studied. The initial rate (i.e. [Formula: see text] in the first 30 minutes) was higher after animals had been killed traumatically than under Nembutal. The initial rate after Nembutal was indistinguishable from the steady rate (i.e. [Formula: see text] during the period 30–60 minutes) for the group killed traumatically, and both of these rates were independent of animal size. However, the initial rate (traumatic killing) and the [Formula: see text] in the presence of added succinate (whatever the method of killing) both decreased with increasing animal weight. The [Formula: see text] value in succinate was indistinguishable from that in oleate and both were higher than the initial rate. The patterns of respiration observed are discussed in terms of O2and substrate availability and of a possible carrying over of a metabolic stimulation from in vivo to in vitro after traumatic killing.