Pharmacology of Autacoids

Autacoids, also known as autocoids, are biological factors resembling local hormones. They are produced, act, and are metabolized locally within the body, influencing activities of various tissues such as smooth muscles, glands, nerves, platelets, and more (1). Notable autacoids include eicosanoids, angiotensin, neurotensin, nitric oxide, kinins, histamine, serotonin, endothelins, and palmitoylethanolamide.

Autacoids are classified into several categories:

  1. Amine Autacoids: This group includes histamine and serotonin (5-Hydroxytryptamine or 5-HT) (2).
  2. Lipid-derived Autacoids: This category encompasses prostaglandins and leukotrienes.
  3. Peptide Autacoids: Examples are bradykinin and angiotensinogen.
  4. Miscellaneous: This includes cytokines (Interleukins, TGF-beta, TNF-alpha, Epidermal Growth Factors) and gastrointestinal peptides (bombesin, gastrin, Vasoactive intestinal peptide/VIP) (2).

Specific autacoids and their effects include:

  • Histamine: Associated with allergic reactions, histamine impacts various body systems, including the nervous, cardiovascular, respiratory, gastrointestinal systems, and the uterus. It causes symptoms like flushing, vasodilation, pain, hypotension, tachycardia, angioedema, bronchospasm, and increased gastric acid secretion (2).
  • Serotonin: Derived from tryptophan, serotonin is found mostly in the alimentary canal and the nervous system. It regulates mood, appetite, sexual desire, attitude, memory, and behavior. Variations in serotonin levels are linked to conditions such as obsessive-compulsive disorder, pulmonary hypertension, depression, and suicidal ideation (2).
  • Prostaglandins: These are hormone-like lipid compounds from fatty acids. They play roles in blood pressure regulation, inflammation, uterine contraction, pain and fever management, gastrointestinal functions, immune system modulation, respiratory system functioning, renal system activities, and platelet aggregation (2).

These substances act as local hormones, significantly affecting various physiological and pathophysiological conditions. Although their primary impact is local, they can have systemic effects when transported via the bloodstream (1).

References:

  1. Wikipedia. Autacoid. Available from: https://en.wikipedia.org/wiki/Autacoid.
  2. PharmaCampus. Autacoids. Available from: https://pharmacampus.in/autacoids-histamine-serotonin-and-prostaglandins.

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