Soulier P, Peyraud-Waitzenegger M, Peyraud C, Barthelemy L
U.A. C.N.R.S., Université de Bretagne Occidentale, France.
Exp Biol. 1988;47(4):243-50.
A study of the effects of arterial pressure changes on heart rate and ventilation was carried out on the eel (Anguilla anguilla L.). The anatomical characteristics of this fish enabled extracorporeal circulation in both the ventral and dorsal aorta to be set up. The pressure was changed mechanically, either by clamping external circulations or, in some cases, by modifying the frequency of a pulsatory pump placed in series with the heart, thus ensuring constant blood flows in the ventral aorta. The maximal pressure decreases obtained by clamping the external ventral aorta circulation (70%-80%) failed to induce significant changes in either heart rate or ventilation. An increase of arterial pressure up to about 50% of the control values did not induce bradycardia and ventilatory response. In the range of 50%-100% increase, a weak decrease of heart rate and slight hyperventilation were observed. Such a ventilatory response was contrary to the hypoventilation classically reported in mammals when systemic arterial pressure was increased, but similar to the hyperventilation observed when blood pressure was increased in the pulmonary arteries. The results emphasized functional analogies in regulation, originating from the circulatory bed, between the two highly compliant circulatory systems: fish circulation and pulmonary circulation of mammals.
