TABLE 2.
Antagonists at H2-histamine receptors.
| Antagonist name | −lg IC50 | Inverse agonism | Tissue studied | References |
|---|---|---|---|---|
| GASTROINTESTINAL DRUGS: | ||||
| Cimetidine | 6.18 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| Ranitidine | 6.79 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| Nizatidine | 7.10 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| Burimamide | 17.16 | − | 1Transfected Chinese hamster ovary cells 2Guinea pig right atrium | 1 Smit et al. (1996b) |
| 27.8 | 2 Black et al. (1972) | |||
| Zolatidine | 7.39 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| Tiotidine | 7.93 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| Famotidine | 8.34 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| ICI 162846 | 8.43 | + | Transfected Chinese hamster ovary cells | Baker (2008) |
| PSYCHIATRIC DRUGS: | ||||
| Amitriptyline | 5.72 or 6.95 | + | 1Neuronal cells | 1 Kanba and Richelson (1983) |
| 2Baculovirus system | 2 Appl et al. (2012) | |||
| 3Langendorff-heart H2-TG mouse | 3 Neumann et al. (2021b) | |||
| Imipramine | 5.48 or 6.10 | + | 1Neuronal cells | 1 Kanba and Richelson (1983) |
| 2Baculovirus system | 2 Appl et al. (2012) | |||
| Chlorpromazine | 5.5 or 5.81 | + | 1Neuronal cells | 1 Kanba and Richelson (1983) |
| 2Baculovirus system | 2 Appl et al. (2012) | |||
| Mianserin | 5.55 or 6.35 | + | 1Neuronal cells | 1 Kanba and Richelson (1983) |
| 2Baculovirus system | 2 Appl et al. (2012) | |||
| Haloperidol | 4.54 or 5.94 | + | 1Neuronal cells | 1 Kanba and Richelson (1983) |
| 2Baculovirus system | 2 Appl et al. (2012) |
Synopsis of some relevant histamine receptor antagonists (first column), their affinity (second column, negative decadic logarithm of their inhibitory action) for H2-histamine-receptors, their ability to act as inverse agonists (+, third column), the tissue studied (fourth column) and the references (fifth column). With the exception of burimamide all listed drugs are inverse agonists. The upper half consists of antagonists designed to be specific antagonists at H2-histamine-receptors and were initially developed to block these receptors in the gastrointestinal tract. The lower half of Table 2 lists drugs used in psychiatry to treat psychosis or depression. In early studies (see text) these compounds were shown to antagonize the stimulatory effect of histamine on the activity of adenylyl cyclases from the guinea pig brain or guinea pig heart. Baker (2008) used human H2-histamine receptors for transfection experiments, thus these data are clinically of special relevance and were therefore chosen to be presented here. Lower affinities are from Kanba and Richelson in cells and higher affinity values are from Appl et al. (2012) where recombinant receptors produced in a baculovirus system were used.