Veterinary Neuropharmacology

AUTACOIDS

• Autacoids are a group of diverse substances produced by a wide variety of cells in the body.
• The term autacoid is derived from Greek word meaning “Self remedy” (Autos – self, akos – remedy or healing substance).
• These substances have intense biological activity.
• They generally act locally (within inflammatory pockets) at the site of their synthesis and release.
• They are also known as local hormones.
• These substances differ from the other hormones in the following points.
  • Hormones are produced by specific cells while autacoids, are produced by a wide variety of cells.
  • Hormones are transported through circulation to act at distant target organ while autacoids act at the site of synthesis and release.
  • Hormones generally act slowly while autacoids act fast.

Clinical relevance

• They are involved in a number of physiological and pathological processes, especially to injury and immunological insult.
• They also serve as transmitters or modulators of the nervous system.
• They are classified as follows based on their structure.
• Amine autacoids – Histamine, 5-hydroxy tryptamine ( 5 HT, serotonin)
• Peptide autacoids - Plasma kinins ( Bradykinin, Kallidin ), Angiotensin
• Lipid derived autacoids - Prostaglandins, Leukotrienes,Platelet activating factor(PAF).
•  Cytokines, gastrin, somatostatin and vasoactive intestinal polypeptide(VIP) are also categorised as autacoids .