Binding, antagonist/receptor

Although this correlation uses rather crude data it gives a clear indication that the actual antagonist/receptor binding is the same at both the cardiac and bronchial sites and indicates that cardioselectivity is a function of distribution to the micro-environment of the receptor site. Some experimental evidence supporting this conclusion is now available from biochemical studies on isolated membrane fragments derived from heart and lung. ... 

Murphy, K.M.M., Snyder, S.H. Calcium antagonist receptor binding sites labeled with pH] Nitrendipine, Eur. J. Pharmacol. 1982, 77, 201-202. 

It can be seen that the equality defined in Equation 4.32 is true only when ICSo = KB (i.e., the concentration of a non-competitive antagonist that reduces the binding of a tracer ligand by 50% is equal to the equilibrium dissociation constant of the antagonist-receptor complex). 

As discussed in Chapter 7, antagonists may bind to a separate loci on the receptor and thereby allosterically modify the affinity of the receptor for the agonist. The maximal change in the agonist affinity is denoted by a term a. It is useful to distinguish allosteric effects in terms of whether the modulator affects signaling and affinity or just affinity. In the latter situation, the modulator produces parallel shifts to the right of the concentration response curve up to a maximal point. This is discussed in Section 7.4.1 (t, = 1). Under these circumstances, the curve for... 

Inhibition constants (Kj) of 26 narcotic analgesic agonists and antagonists as obtained in 4 receptor binding tests (EKC, DHM, DADLE and NAL) [45],... 

Fig. 37.4. Spectral map of the 26 opioid agonists and antagonists in 4 receptor binding tests, as described by Table 37.7 [45, 46]. Circles refer to the compounds. Squares represent the binding tests. Areas of circles and squares are proportional to the marginal mean affinities in the table. The lines that join the three poles (DHM, DADLE and EKC) of the map represent axes of contrast between the p-, 8-and K-opioid receptors. The horizontal and vertical components represent 18 and 79%, respectively, of the interaction in the data.

B-Lactamase inhibitors, 31 (1994) 297 Leprosy, chemotherapy, 20 (1983) 1 Leukocyte elastase inhibition, 31 (1994) 59 Leukotriene D4 antagonists, 38 (2001) 249 Ligand-receptor binding, 23 (1986) 41 Linear free energy, 10 (1974) 205... 

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