Related Experiment Video
Updated: Aug 2, 2026

Delivery of In Vivo Acute Intermittent Hypoxia in Neonatal Rodents to Prime Subventricular Zone-derived Neural Progenitor Cell Cultures
Published on: November 2, 2015
Role of hypoxemia in sleep apnea-induced sympathoexcitation
M L Smith1, O N Niedermaier, S M Hardy
1Department of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
Abstract:
The importance of hypoxemia in determining sympathoexcitation during obstructive sleep apnea was examined by comparing changes in efferent sympathetic nerve activity (SNA) during spontaneous obstructive apneas with hypoxemia alone of similar magnitude and duration induced by 1-4 breaths of 100% nitrogen in six patients with obstructive sleep apnea and with spontaneous apneas while breathing 100% oxygen (apnea without hypoxemia) in three patients. In addition, eight control subjects were studied during induced hypoxemia. The magnitude of sympathoexcitation during spontaneous apneas (103 +/- 15%) was more than twice that observed during induced hypoxemia (47 +/- 14%) during episodes in which the nadir of oxygen desaturation (78 +/- 2 and 75 +/- 2%, respectively) and duration of hypoxemia (27 +/- 3 and 33 +/- 3 s, respectively) were the same (P > 0.20). Similarly, in three patients SNA increased 115% during normoxic spontaneous obstructive apneas, but increased only 43% during hyperoxic spontaneous obstructive apneas in which oxygen saturation did not decrease significantly. Sympathetic neural responses to induced hypoxemia in control subjects (17 +/- 7%) were significantly less than that of the sleep apnea patients. We conclude that hypoxemia contributes importantly, but is not the sole determinant of the sympathoexcitation provoked during episodes of obstructive sleep apnea.
Related Concept Videos
Physiological Control of Respiration
Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
Regulation of Ventilation
The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
Hypoxia
Types of Hypoxia
There are four primary types of hypoxia, each resulting from a different cause:
1. Anemic hypoxia: This type occurs due to insufficient oxygen delivery caused by a lack of red blood cells (RBCs) or RBCs with abnormal or...
Chemical Factors Affecting Respiration Centers
CO2 has a potent influence on respiration and is strictly regulated. Under...
Hyperpnea and Hyperventilation
Acute Respiratory Failure-II
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
Sleep Apnea
The condition is more prevalent among...

