The affinity of betaxolol, a β1-adrenoceptor-selective blocking agent, for β-adrenoceptors in the bovine trachea and heart
| Autor: | Akihiro Narimatsu, Hiroshi Tsuchihashi, Eisaku Satoh, Yoshiaki Hosohata, Takafumi Nagatomo |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
medicine.medical_specialty
Biology Pharmacology Betaxolol Butoxamine Beta-1 adrenergic receptor Radioligand Assay Internal medicine Receptors Adrenergic beta medicine Radioligand Animals Antagonist Heart Atenolol Trachea Endocrinology Mechanism of action Organ Specificity Cattle medicine.symptom Research Article medicine.drug |
| Zdroj: | British Journal of Pharmacology. 108:484-489 |
| ISSN: | 0007-1188 |
| Popis: | 1. The specificity of betaxolol, a beta-adrenoceptor antagonist, for beta 1- and beta 2-adrenoceptors was compared with that of other beta-antagonists, atenolol, ICI-118551, butoxamine and (+/-)-propranolol, in the bovine trachea and heart by competitive interaction with [3H]-CGP12177 as a radioligand. 2. The radioligand Kd values were 0.75 +/- 0.12 and 1.60 +/- 0.11 nM in the trachea and heart, respectively, and the Bmax values were 34.00 +/- 4.41 and 21.54 +/- 2.94 fmol mg-1 protein, respectively. 3. Using ICI-118551, we determined the ratio of beta 1:beta 2-adrenoceptors in the trachea and heart to be approximately 29:71 and 56:44, respectively. 4. In the trachea, a beta 2-predominant tissue, betaxolol and atenolol were more selective for beta 1-adrenoceptor binding sites than beta 2-adrenoceptor binding sites, whereas ICI-118551 and butoxamine were more selective for beta 2-adrenoceptor binding sites. 5. The beta 1-selectivity of betaxolol was 2.2 and 2.7 fold higher than that of atenolol in the bovine trachea and heart. These findings suggest that betaxolol may be useful in the treatment of hypertension, cardiac arrhythmia and angina pectoris. |
| Databáze: | OpenAIRE |
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