Which action is NOT one of the main actions of inflammatory mediators?

In the context of inflammatory mediators, their primary role involves enhancing the inflammatory response, which includes various actions like vasodilation, increased capillary permeability, and the promotion of coagulation to prevent blood loss.

Decreased capillary permeability is not among the main actions of inflammatory mediators. Instead, inflammatory mediators like histamines and prostaglandins actually increase capillary permeability. This mechanism allows essential immune cells and proteins to exit the bloodstream and reach sites of injury or infection, fostering tissue repair and an effective immune response.

The other options, such as vasodilation, which increases blood flow to the affected area, and increased coagulation, which helps prevent excessive bleeding during tissue injury, are part of the orchestrated response initiated by inflammatory mediators to facilitate healing and combat pathogens. Thus, decreased capillary permeability stands out as the action that is not aligned with the functional profile of inflammatory mediators.