Related Experiment Videos
Role of nitric oxide in the control of mitochondrial function
P R Forfia1, T H Hintze, M S Wolin
1Department of Physiology, New York Medical College, Valhalla 10595, USA.
Abstract:
In summary, NO is capable of decreasing mitochondrial respiration in a variety of mammalian tissues. This effect is mediated primarily via binding of NO to the O2 binding site of cytochrome oxidase. This highly sensitive interaction presumably reflects a remnant homology between cytochrome oxidase and bacterial nitrate reductase. This effect has been demonstrated at physiologic levels of NO, highlighting the role for NO in the tonic control of cellular respiration. As this inhibition is dependent upon the levels figure: see text[ of NO and O2 in the tissue, various states of NO production and oxygen supply dictate the ultimate respiratory rate of the mitochondria. Furthermore, deviation from a physiologic NO: O2 may lead to an exacerbation of pathologic states, such as congestive heart failure and septic shock. Thus, NO may play a crucial role in the control of cellular respiration, providing an additional mechanism of action for this biologically diverse molecule that is distinct yet inseparable from its dilator effect on blood vessels.
Insights
Nitric oxide (NO) inhibits mitochondrial respiration by binding to cytochrome oxidase, impacting cellular energy production. This NO-mediated control is vital for regulating respiration and may influence conditions like heart failure.
Area of Science:
- Biochemistry
- Cellular Respiration
- Physiology
Background:
- Nitric oxide (NO) is a signaling molecule with diverse physiological roles.
- Mitochondrial respiration is crucial for cellular energy production.
- The interaction between NO and cellular respiration is not fully understood.
Purpose of the Study:
- To investigate the effect of nitric oxide (NO) on mitochondrial respiration.
- To elucidate the mechanism by which NO affects cellular respiration.
- To explore the physiological relevance of NO-mediated respiratory control.
Main Methods:
- Studies in various mammalian tissues.
- Analysis of NO binding to cytochrome oxidase.
- Assessment of NO and oxygen levels in relation to respiratory rates.
Main Results:
- Nitric oxide (NO) decreases mitochondrial respiration across mammalian tissues.
- NO binds to the O2 binding site of cytochrome oxidase, inhibiting its function.
- This inhibition occurs at physiological NO levels, indicating a role in tonic control.
- Respiratory rates are dependent on the interplay of NO and oxygen availability.
Conclusions:
- Nitric oxide (NO) plays a critical role in the tonic control of cellular respiration.
- The interaction with cytochrome oxidase represents a distinct mechanism of NO action.
- Dysregulation of the NO:O2 balance may exacerbate pathological conditions like congestive heart failure and septic shock.