In this issue, Fletcher et al 1 report that repetitive brief hypoxia applied during a 7-hour period per day for up to 35 days causes diurnal elevation of blood pressure in rats. This significant finding examines the mechanism of chronic, reversible arterial hypertension correlated with sleep apnea syndrome.The hemodynamic pattern of obstructive sleep apnea (OSA) (blood pressure rise at the nadi...

Effects of acute hypercapnia on the cardiovascular system (CYS) were studied in the anesthetized cat. After surgery the animal was exposed to a gas mixture of 12% CO2 and 25% O2 in nitrogen, and hypercapnia with low levels of arterial pH (pHa) was produced for 20 minutes. In the second run the same level of hypercapnia was induced by ventilating the same cat from the above gas mixture but ...

say. J Clin Endocrinol Metab 27: 973-990, 1967 16. 13. Brecher G, Cronkite EP: Morphology and enumeration of human blood platelets. J Appl Physiol 3: 365-377, 1950 14. Baumgartner HR: Eine neue Methode zur Erzengung von Thromben 17. durch gesielte uberdehnung der Gefasswant. Z Ges Exp Med 137: 227-249, 1963 15. Stemerman MB, Spaet TH, Pitlick F, Cintron J, Lejnieks I, Tiell ML: 18. The pattern ...

The renin response to hypoxia in late gestation fetal sheep has been well characterized. However, the renin response to asphyxia-the combination of hypoxia and hypercapnia-has not been extensively studied. The purpose of this study was to determine 1) the interaction of hypoxia and hypercapnia in the control of renin secretion in late gestation fetal sheep and 2) the role of peripheral arterial...

The role of the carotid bifurcation chemoreceptors in mediating the cerebrovascular response to altered arterial PCO2 has been suggested to be large. In the present study the cerebrovascular response to raised PCO2 was measured in a group of baboons before and after bilateral inactivation of the carotid bodies. The results suggest that these chemoreceptors do play a part in the cerebral vasodil...

The peripheral hyperosmolarity elicited by intravenous infusion of hypertonic saline brings potential benefits to the treatment of hemorrhage. The neural mechanisms involved in these beneficial effects remain unknown. The present study examines the role of carotid chemoreceptors in cardiovascular responses induced by hypertonic saline after hypovolemic hemorrhage in rats. Male Wistar rats (300-...

We have previously shorn that the respiratory control system in the cat has the requisite sensitivity and speed to respond to changes in arterial pH which are equal to, or smaller than, the normal fluctuations in pH with respiration. A respiratory response was only observed when the changes in pH were produced by alterations in PCO2 and not when they were induced by non-gaseous acids. We descri...

Both respiratory centres and the preganglionic vagal motoneurones, which control respiratory (striated) and airway (smooth) muscles respectively, receive information on the lungs, the circulation and the skeletal and respiratory muscles. Each of these nervous pathways has two components: one is phasic, i.e. in phase with biological rhythms, and comes from mechanoreceptors connected to large mye...

Prabhakar, Nanduri R., and Ying-Jie Peng. Peripheral chemoreceptors in health and disease. J Appl Physiol 96: 359–366, 2004; 10.1152/japplphysiol. 00809.2003.—Peripheral chemoreceptors (carotid and aortic bodies) detect changes in arterial blood oxygen and initiate reflexes that are important for maintaining homeostasis during hypoxemia. This mini-review summarizes the importance of peripheral ...