Responses of atria 1 and aortic baroreceptors to nonhypotensive hemorrhage and to tranfusiod

GUPTA, P.D.,J.P. HENRY, R. SINCLAIR,AND R. VON BAUMGARTEN. Responses of atrial and aortic baroreceptors to nonhypotensiue hemorrhage and transfusion. Am. J. Physiol. 21 I (6) : Ipg-1437. 1g66.-The activity of aortic and atria1 type B baroreceptors was compared in 2 I experiments in 15 chloralose-in-saline anesthetized dogs in the course of stepwise bleeding and transfusion. When the alteration-in-pulse frequency was taken into account, the integrated ,impulse rate or “drive” from the aortic receptors was found to remain essentially constant during moderate volume changes. However, there was a sharp alteration in the activity of the atria1 receptors. This amounted to an 807~ decrease in firing rate with a 20 y0 blood volume loss and a fourfold increment with a 20% increase in blood volume. The triggering during nonhypotensive hemorrhage of various homeostatic responses such as tachycardia and the release of antidiuretic hormone is discussed in relation to the above disparity of receptor drives.