| Autor: |
Mohamed S. Elfellah, John L. Reid |
| Rok vydání: |
1989 |
| Předmět: |
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| Zdroj: |
European Journal of Pharmacology. 173:85-92 |
| ISSN: |
0014-2999 |
| Popis: |
The effect of chronic pretreatment of guinea pigs with various s-adrenoceptor antagonists on the binding characteristics of the radioligand 125I-cyanopindolol (ICYP) and responsiveness of adenylate cyclase to isoprenaline in the gastrocnemius muscle (s2-adrenoceptors) and left ventricle (s1-adrenoceptors) were compared. Pretreatment of guinea pigs with propranolol or ICI 118,551 for one week significantly increased the density of the s2-adrenoceptors in the gastrocnemius muscle. Atenolol pretreatment for one week did not affect the density of the receptors. Pretreatment of the animals with pindolol for one week reduced the density of s2-adrenoceptors in skeletal muscle. In the left ventricle pretreatment of the guinea pigs with any of the antagonists did not alter either the density or the KD of s1-adrenoceptors. The responsiveness of adenylate cyclase to isoprenaline (10−4 M) in the left ventricle or skeletal muscle was not affected when the guinea pigs were pretreated with propranolol. Pretreatment of the guinea pigs with reserpine (0.5 mg · kg−1) intraperitoneally for one week, to deplete catecholamines did not affect s-adrenoceptor density or KD in the left ventricle or skeletal muscle. We conclude that the regulation of s-adrenoceptors by the antagonist may not be caused by the prevention of the access of endogenous agonists to s-adrenoceptors and it is dependent on the selectivity of the antagonist and on the susceptibility of the receptors to regulation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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