Table 4

Pharmacological characterization of muscarinic receptor subtypes

Potency orderAcetylcholine and carbachol do not discriminate subtypes
Selective agonists
 AF-DX 1166.4–6.97.1–7.25.9–6.66.6–7.06.6
 AF-DX 3847.3–7.58.2–9.07.2–7.88.0–8.76.3
 pFHHSi D7.2–7.56.0–6.97.8–
  • 4-DAMP, 4-diphenylacetoxy-N-methyl piperidine methiodide. Antagonist affinities are expressed as −logK i or −log K B values. Adapted from Alexander and Peters (1999), Birdsall et al. (1998), Caulfield (1993), Caulfield et al. (1998), and Eglen and Watson (1996).

  • 4-a No subtype-selective agonists of high intrinsic efficacy are available; thus, muscarinic receptor subtypes are pharmacologically defined by a combination of several antagonists.