Gasboðefni

Gasboðefni, often translated as "gas messengers" or "gasotransmitters," are a class of signaling molecules that exist as gases. Unlike typical neurotransmitters or hormones that bind to specific receptors on cell surfaces or within cells, gasboðefni are able to freely diffuse across cell membranes. This unique property allows them to act locally within tissues or even between adjacent cells without requiring complex transport mechanisms.

The most well-studied gasboðefni include nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and ammonia (NH₃). Each of these molecules has distinct biological roles. Nitric oxide is crucial for vasodilation, regulating blood pressure, and is involved in neurotransmission and immune responses. Carbon monoxide, though historically known for its toxicity, also plays roles in signaling, particularly in the cardiovascular and nervous systems. Hydrogen sulfide has emerged as a significant gasotransmitter involved in inflammation, cell survival, and metabolism. Ammonia's role as a gasotransmitter is less understood but is thought to be involved in cellular signaling pathways.

The synthesis of gasboðefni is typically enzymatic. For example, nitric oxide is produced by nitric oxide synthases (NOS), and carbon monoxide is generated from the breakdown of heme. Their signaling often involves post-translational modification of target proteins, such as S-nitrosylation, S-glutathionylation, and carbamylation, which can alter protein function. Due to their gaseous nature and rapid diffusion, gasboðefni often exert short-lived and localized effects, making their study and manipulation challenging.