title: Autonomic regulation of organ vascular resistances during hypoxemia in the cat.
abstract: This study aimed to dissect the roles played by the autonomic interoreceptors, the carotid bodies (cbs) and the aortic bodies (abs) on the vascular resistances of several organs in anesthetized, paralyzed, artificially ventilated cats challenged by systemic hypoxemia. Two 15 min challenges stimulated each of 5 animals in two different groups: (1) in the intact group hypoxic hypoxia (10% O2 in N2; HH) stimulated both abs and cbs, increasing neural output to the nucleus tractus solitarius (NTS); (2) in this group carbon monoxide hypoxia (30% O2 in N2 with the addition of CO; COH) stimulated only the abs, increasing neural output to the NTS. (3) In the second group in which their bilateral aortic depressor nerves had been transected only the cbs increased neural output to the NTS during the HH challenge; (4) in this aortic body resected group during COH neither abs nor cbs increased neural traffic to the NTS. CO and 10% O2 reduced Hb saturation to the same level. With the use of radiolabeled microspheres blood flow was measured in a variety of organs. Organ vascular resistance was calculated by dividing the aortic pressure by that organ's blood flow. The spleen and pancreas revealed a vasoconstriction in the face of systemic hypoxemia, thought to be sympathetic nervous system (SNS)-mediated. The adrenals and the eyes vasodilated only when cbs were stimulated. Vasodilation in the heart and diaphragm showed no effect of chemoreceptor stimulated increase in SNS output. Different chemoreceptor involvement had different effects on the organs.
authors.affiliation: Department of Environmental Health Sciences, (Division of Physiology), The Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA; Departments of Physiology and of Medicine, School of Medicine, The Johns Hopkins University, Baltimore, MD. Electronic address: rfitzger@jhsph.edu.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Fitzgerald
authors.forename: Gholam Abbas
authors.initials: GA
authors.lastname: Dehghani
authors.forename: Samara
authors.initials: S
authors.lastname: Kiihl
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000098:blood supply / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D002415:Cats; D005260:Female; D000860:Hypoxia / Q000503:physiopathology*; D007422:Intestines / Q000098:blood supply / Q000502:physiology; D008099:Liver / Q000098:blood supply / Q000502:physiology; D008297:Male; D013270:Stomach / Q000098:blood supply / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology
keywords: Arterial chemoreceptors; Autonomic nervous system; Hypoxemia; Organ vascular resistance