Which statement accurately describes NO signaling in exercise adaptations?

Which statement accurately describes NO signaling in exercise adaptations?

• A. NO has no role in signaling for mitochondrial biogenesis.
• B. NO is not involved in muscle signaling.
• C. NO only modulates blood pressure.
• D. NO participates in signaling for mitochondrial biogenesis.

Answer: (D)

Nitric oxide acts as a signaling molecule during exercise, not just a vasodilator. During activity, NO is produced by endothelial and muscle cells in response to shear stress and Ca2+ signals. It diffuses into muscle fibers and activates pathways that promote mitochondrial biogenesis, notably through the soluble guanylate cyclase–cGMP signaling axis and its interaction with metabolic regulators like AMPK and PGC-1α. This signaling supports the growth of mitochondria and the enhanced oxidative capacity typical of training adaptations. So NO participates in signaling for mitochondrial biogenesis, rather than having no role or being limited to blood pressure effects.

Nitric oxide acts as a signaling molecule during exercise, not just a vasodilator. During activity, NO is produced by endothelial and muscle cells in response to shear stress and Ca2+ signals. It diffuses into muscle fibers and activates pathways that promote mitochondrial biogenesis, notably through the soluble guanylate cyclase–cGMP signaling axis and its interaction with metabolic regulators like AMPK and PGC-1α. This signaling supports the growth of mitochondria and the enhanced oxidative capacity typical of training adaptations. So NO participates in signaling for mitochondrial biogenesis, rather than having no role or being limited to blood pressure effects.