Molecules 2001, 6, 142-193 molecules ISSN 1420-3049 http://www.mdpi.org Review Muscarinic Receptor Agonists and Antagonists Kenneth J. Broadley1 and David R. Kelly2,* 1Division of Pharmacology, Welsh School of Pharmacy and 2Department of Chemistry, Cardiff University, Cathays Park, Cardiff, CF10 3TB, UK *To whom correspondence should be addressed; e-mail:
[email protected] Received: 2 August 2000; in revised form 16 January 2001 / Accepted: 16 January 2001 / Published: 28 February 2001 Abstract: A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes). Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted. Keywords: Alzheimer’s disease, nicotine, acetylcholine, arecoline, himbacine, tacrine, cyclostelletamines, intramolecular Diels-Alder reaction, indole alkaloids Contents 1 The Pharmacology of Muscarinic Receptors 1.1 Introduction 1.2 Muscarinic receptor subtypes Molecules 2001, 6 143 2 Pharmacological Effects of Agonists and Therapeutic Applications 2.1 Cardiovascular system 2.2 Gastointestinal tract 2.3 Other smooth muscle 2.4 Glandular secretions 2.5 The eye 2.6 Central nervous