title: Development of muscarinic m3 and m4 receptor antibodies with pharmacological activities.
abstract: OBJECTIVE
  To investigate the feasibility of developing subtype-selective anti-receptor antibodies with pharmacological activities for the study of subtypes of receptors.
  
  
  METHODS
  New Zealand white rabbits were immunized with synthesized subtype-selective peptide segments of m3 and m4 receptors to develop antibodies. The effects of the antibodies on ligand-binding to muscarinic receptors were studied by competitive radioligand assay. The effects of the prepared antibodies on the contraction or relaxation activity of ACh in isolated rat ilea and aortic rings were studied.
  
  
  RESULTS
  Antibodies against synthesized m3 and m4 receptor subtype-selective peptides were successfully prepared. Both antibodies inhibited [3H]QNB binding to muscarinic receptors with different maximal inhibitions which may be the proportions of m3 or m4 subtypes among the total muscarinic receptors in the tissues. The maximal inhibitory rates in rat cerebral cortex, myocardium, and salivary glands were 12.1% +/- 2.1%, 15.7% +/- 1.1%, and 63.6% +/- 2.8% for m3 antibodies, whereas 28% +/- 6%, 19.3% +/- 2.6%, and 1.6% +/- 1.4% for m4 antibodies respectively. The m3 antibodies inhibited the contraction activity of ACh in isolated rat ilea and the relaxation activity of ACh in isolated rat aortic rings.
  
  
  CONCLUSIONS
  It is feasible to develop subtype-selective anti-receptor antibodies as new tools in the study of the functions of m3 and m4 subtypes of muscarinic receptors.
authors.affiliation: Department of Pharmacology, Sun Yat-sen University of Medical Sciences, Guangzhou, China.
authors.forename: H Y
authors.initials: HY
authors.lastname: Wang
authors.forename: S J
authors.initials: SJ
authors.lastname: Zeng
authors.forename: P X
authors.initials: PX
authors.lastname: Qiu
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001013:Aorta, Thoracic / Q000187:drug effects; D001667:Binding, Competitive; D002540:Cerebral Cortex / Q000378:metabolism; D000939:Epitopes; D007082:Ileum / Q000187:drug effects; D007106:Immune Sera / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D011817:Rabbits; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D043587:Receptor, Muscarinic M3; D043588:Receptor, Muscarinic M4; D011976:Receptors, Muscarinic / Q000276:immunology*; D012469:Salivary Glands / Q000378:metabolism; D014664:Vasodilation / Q000187:drug effects
chemical_list: D000906:Antibodies; D000939:Epitopes; D007106:Immune Sera; D043587:Receptor, Muscarinic M3; D043588:Receptor, Muscarinic M4; D011976:Receptors, Muscarinic