The importance of muscarinic receptors in domestic animal diseases and therapy: Current and future perspectives

• The parasympathetic nervous system controls functions of several organs in domestic animals.
• Different muscarinic acetylcholine receptor subtypes are differently distributed throughout the body.
• Receptors play pivotal role in the pathophysiology of several diseases in domestic animals.
• Identifying these receptors helps to present novel perspectives on antimuscarinic drugs for animals.

This review provides an overview of the early and current literature including contributions that highlight the parasympathetic cholinergic receptor systems in domestic animal tissues. Muscarinic acetylcholine receptors (mAChRs) belong to the subfamily of G protein-coupled receptors and regulate many fundamental functions of the central and peripheral nervous systems and have been subject to research over at least 40 years. Nonetheless, there are few studies specifying mAChRs in domestic animal tissues.This review focuses on the pharmacology of muscarinic acetylcholine receptor (mAChR) system and its pathological as well as the therapeutic importance in organ systems of domestic animals. Illustration and discussion of recent advances in distribution, function, biochemistry and pharmacology of mAChRs are followed by summaries of the involvement of this family of receptors in cardiovascular, respiratory, neurological, gastrointestinal (GI) and urological diseases as well as in anaesthesia and toxicology.Specific functions of mAChRs are described in detail including subtype characterization, smooth muscle functions, signal transduction and regulation. Due to their wide tissue distribution, mAChRs have shown promise as targets for the treatment of some animal diseases such as equine recurrent airway obstruction, glaucoma, abnormalities of gastric acid secretion and GI disturbances including colic.