Abstract
The interaction of a drug with a specific site of tissue cells, i.e. drug receptor, is generally assumed for explaining the mode of action of some drugs, but very little is known on its substantial existence and further on its chemical natures. The best method available for solving this problem is specific alkylation of the receptor with a labeled β-haloethylamine in combination with an antagonist or agonist. Testing the parallelism between incorporated radioactivity and pharmacological phenomena, rather specific labeling of drug receptors can be expected. The point on which emphasis was laid in this study was to distinguish the pharmacological blocking effect of dibenamine from its chemical alkylating ability. All the amount of radioactivity found in the tissue is not limited to dibenamine concerned in the pharmacological blocking action.
During this study (1-4) several papers were published on specific labeling of α-adrenergic receptor in various tissues with labeled β-haloethylamines utilizing simultaneously an antagonist and/or an agonist (5-10).
In these reports, however, the correlation between the incorporated radioactivity and the pharmacological effect of a β-haloethylamine was not sufficiently confirmed.
To avoid these weak points following experimental designs were chosen.
1. Three kinds of pharmacologic protective drugs were used.
2. Three kinds of pharmacologically non-protective drugs were also employed in the same manner as the protective drugs.
3. Six kinds of tissues with different histamine sensitivities were treated in the same way as the cat small intestine.
These principles will testify the assumption that the receptor is specifically labeled with dibenamine.
