Related Experiment Video

Updated: Sep 28, 2026

Experimental Approach to Examine Leptin Signaling in the Carotid Bodies and its Effects on Control of Breathing
05:45

Experimental Approach to Examine Leptin Signaling in the Carotid Bodies and its Effects on Control of Breathing

Published on: October 25, 2019

Central heme oxygenase-carbon monoxide pathway in the control of breathing under normoxia and hypoxia

Flávia M Paro1, Alexandre A Steiner, Patricia M De Paula

  • 1Departamento de Morfologia, Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirão Preto, Ribeirão Preto SP, Brazil.

Respiratory Physiology & Neurobiology
|October 17, 2002
PubMed

Insights

The central heme oxygenase-carbon monoxide pathway does not influence breathing responses to low oxygen. This study found no evidence that this pathway regulates hypoxia-induced hyperventilation in rats.

Area of Science:

  • Physiology
  • Neuroscience
  • Biochemistry

Background:

  • Endogenous carbon monoxide (CO) is produced from heme catabolism by heme oxygenase (HO).
  • The central nervous system's role in regulating respiratory responses to hypoxia is complex.
  • The heme oxygenase-carbon monoxide (HO-CO) pathway is a potential regulator of physiological processes.

Purpose of the Study:

  • To investigate the involvement of the central HO-CO pathway in hypoxia-induced hyperventilation.
  • To test if inhibiting or inducing the HO-CO pathway affects respiratory control during low oxygen conditions.

Main Methods:

  • Conscious rats were administered intracerebroventricular (i.c.v.) injections of a HO inhibitor (ZnDPBG) or heme-lysinate.
  • Respiratory frequency (f), tidal volume (VT), and pulmonary ventilation (VE) were measured using body plethysmography.
  • Hypoxia was induced using 7% inspired oxygen.

Main Results:

  • Hypoxia significantly increased pulmonary ventilation (VE) by elevating respiratory frequency (f) and tidal volume (VT).
  • Neither the HO inhibitor (ZnDPBG) nor heme-lysinate altered basal VE or the hyperventilatory response to hypoxia.
  • Vehicle administration also did not affect respiratory parameters.

Conclusions:

  • The central heme oxygenase-carbon monoxide pathway does not appear to play a significant role in mediating the respiratory response to acute hypoxia in rats.
  • These findings do not support the hypothesis that the HO-CO pathway is involved in hypoxia-induced hyperventilation.

More Related Videos

A Model to Simulate Clinically Relevant Hypoxia in Humans09:54

A Model to Simulate Clinically Relevant Hypoxia in Humans

Published on: December 22, 2016

The c-FOS Protein Immunohistological Detection: A Useful Tool As a Marker of Central Pathways Involved in Specific Physiological Responses In Vivo and Ex Vivo05:44

The c-FOS Protein Immunohistological Detection: A Useful Tool As a Marker of Central Pathways Involved in Specific Physiological Responses In Vivo and Ex Vivo

Published on: April 25, 2016

Related Concept Videos

Physiological Control of Respiration01:23

Physiological Control of Respiration

Introduction
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...
Chemical Factors Affecting Respiration Centers01:31

Chemical Factors Affecting Respiration Centers

Chemical factors such as changing CO2, O2, and H+ levels in arterial blood play a critical role in influencing respiration depth and rates. These variations are detected by chemoreceptors—specialized sensors located in two primary body areas. Central chemoreceptors are found throughout the brain stem, including the ventrolateral medulla, while peripheral chemoreceptors are located in the aortic arch and carotid arteries.
CO2 has a potent influence on respiration and is strictly regulated. Under...
Hypoxia01:23

Hypoxia

Hypoxia is a medical condition characterized by an inadequate oxygen supply to body tissues. It typically manifests as a bluish discoloration of the skin and mucosae, especially in fair-skinned individuals, when hemoglobin (Hb) saturation drops below 75%.
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...
Oxygen Transport in the Blood01:27

Oxygen Transport in the Blood

Hemoglobin (Hb) is a crucial molecule in the human body, consisting of four polypeptide chains, each bound to an iron-containing heme group. This unique structure enables hemoglobin to bind to oxygen, with each molecule capable of combining with four molecules of oxygen, leading to rapid and reversible oxygen loading. When fully loaded with oxygen, it is called oxyhemoglobin, while hemoglobin that has released oxygen is called reduced hemoglobin or deoxyhemoglobin. As hemoglobin binds oxygen,...
Physiology of Respiration II: Neurogenic Control of Respiration01:22

Physiology of Respiration II: Neurogenic Control of Respiration

The neurogenic control of respiration coordinates various neural networks and pathways to regulate breathing rate and depth, meeting the body's oxygen and carbon dioxide exchange requirements. This system adapts to physiological and environmental conditions, ensuring optimal breathing patterns.
Central Control
The brainstem is the primary site of central control, hosting respiratory centers:
Respiration and Gaseous Exchange01:20

Respiration and Gaseous Exchange

The intricate interplay between the cardiovascular and respiratory systems is crucial for efficiently transporting respiratory gases throughout the body. Let us explore the cardiovascular system's multifaceted functions, emphasizing its pivotal role in gas exchange.
Respiration involves the exchange of gases, especially oxygen (O2) and carbon dioxide (CO2), between the alveoli and body cells, a process facilitated by blood circulation. As a result, the cardiovascular system, which involves the...