AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 3 216-R219, Copyright © 1982 by American Physiological Society
Circulatory mechanoreceptors in the pond turtle Pseudemys scripta
F. M. Faraci, H. W. Shirer, J. A. Orr and J. W. Trank
This study was undertaken to characterize cardiovascular receptors in the
turtle, Pseudemys scripta, with particular attention being given to neural
activity changes associated with alterations in blood pressure. Vagal
afferent nerve traffic, synchronous with heart contractions, was recorded
in anesthetized artificially ventilated turtles. Action potentials, from
receptors that fired regularly during each heart cycle, occurred during
ventricular systole. Mechanical probing and vascular occlusion indicated
that these receptors were located in the proximal common pulmonary artery
including the bulbus cordis region. Bolus injections of saline into the
ventricle or the common pulmonary artery caused immediate but transient
increases in cardiac synchronous traffic. Prolonged elevation of arterial
and ventricular blood pressure, by either saline injection or arterial
occlusion, caused increases in receptor discharge of the same duration as
the pressure increases. Although these receptors could participate in the
regulation of the systemic and the pulmonary circulation, the physiological
role for them is presently unknown.
