Slow reacting substances (SRS) refer to biological molecules or compounds that are released in response to certain stimuli and trigger a delayed immune response in the body. These substances are typically involved in inflammatory processes and are released by various cells, predominantly mast cells, in response to allergens, pathogens, or injury.
SRS are characterized by their slow release and prolonged effects on target tissues. They include diverse molecules such as leukotrienes, prostaglandins, bradykinin, and histamine. These substances are produced and stored in cells until a stimulus, such as injury or exposure to an allergen, prompts their release. Once released, SRS bind to specific receptors on immune cells and other target cells, triggering a cascade of events that contribute to the inflammation and immune response.
The release of slow reacting substances results in increased blood flow, vascular permeability, and recruitment of immune cells to the affected area. This leads to various physiological responses, including itching, redness, swelling, and pain. In addition, SRS can amplify and prolong the immune response by promoting the release of other inflammatory mediators and by attracting more immune cells to the site of inflammation.
Understanding the role of slow reacting substances is crucial in the diagnosis, treatment, and management of immune-related disorders such as allergies, asthma, and autoimmune diseases. Pharmacological agents that target the action or production of SRS, such as antihistamines or leukotriene inhibitors, are commonly used to alleviate symptoms and reduce inflammation associated with these conditions.
