Baro- and chemoreceptor mechanisms in haemorrhage.

Abstract

The observations summarized here arose out of a systematic examination, made for other purposes, of the effects of haemorrhage in animals of different ages, lightly anaesthetized with sodium barbitone. It became evident that in terms of the criteria detailed below, kittens and young rabbits withstood haemorrhage better than the adults of these species (10, 14). Further analysis showed that the contribution of arterial baroreceptor mechanisms in the maintenance of arterial pressure is relatively greater in adult rabbits and that mechanisms of renal origin have a predominant influence in immature rabbits (15). Both these species, especially the rabbit, are born in a somewhat immature condition. Developmental changes in cardiovascular function must be taken into account when designing appropriate tests of, and in assessing cardiovascular responses to, stimuli.