The effect of ionic strength on cardiac muscarinic receptors

• Published in: British journal of pharmacology Vol. 88; no. 2; pp. 451 - 455
• Main Author: Burgen, A.S.V.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.1986; Nature Publishing
• Subjects: Animals; Applied sciences; Binding, Competitive - drug effects; Biological and medical sciences; Carbachol - pharmacology; Exact sciences and technology; In Vitro Techniques; Male; Medical sciences; Membranes - metabolism; Miscellaneous; Myocardium - metabolism; N-Methylscopolamine; Neuropharmacology; Neurotransmitters. Neurotransmission. Receptors; Other techniques and industries; Pharmacology. Drug treatments; Rats; Rats, Inbred Strains; Receptors, Muscarinic - drug effects; Receptors, Muscarinic - metabolism; Scopolamine Derivatives - pharmacology; Sodium Chloride - pharmacology; Heart; Vertebrata; Agonist; Biological fixation; Mammalia; Rat; Ionic strength; Animal; Rodentia; Muscarinic receptor; Antagonist; Metabolism
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1111/j.1476-5381.1986.tb10223.x

1 The binding of N‐methylscopolamine (NMS) and carbachol to muscarinic receptors in the rat heart has been measured as a function of ionic strength (μ). 2 The binding of NMS was reduced by 3.69 fold for a 10 fold increase in ionic strength. 3 The binding of carbachol was affected in two ways. Firstly, the proportions of the subsites were changed. Above μ = 0.5 M, the superhigh (SH) subsite was converted into the low(L) subsite and above μ = 0.8 M, the high (H) subsite was also converted into the L subsite. Therefore, at high ionic strength, no agonist‐determined subsites can be detected. In addition, increase in ionic strength reduced the binding of carbachol to all subsites and to a much greater extent than for NMS.