| Autor: |
Kousvelari, E E, Kusiak, J W, Hand, A R, Pitha, J, Baum, B J |
| Zdroj: |
The Journal of Pharmacology and Experimental Therapeutics; October 1983, Vol. 227 Issue: 1 p238-243, 6p |
| Abstrakt: |
The interaction of bromoacetylalprenololmenthane (BrAlpM), an irreversible beta adrenergic receptor antagonist, with rat parotid acinar cells was studied in vitro. In the presence of BrAlpM, the rate of (-)-isoproterenol-induced exocrine secretion from cells, measured as percentage of amylase release, was markedly reduced. The concentration of (-)-isoproterenol required to elicit half-maximal protein secretion was about 100 times greater (5 microM) in the presence of 1 microM BrAlpM than in control incubations (0.05 microM). BrAlpM and propranolol were similar in their ability to inhibit parotid protein release (IC50 approximately 10(-7) M). To demonstrate that BrAlpM functioned as an irreversible beta adrenergic antagonist, cells were preincubated with BrAlpM for varying amounts of time and then washed three to six times before adding (-)-isoproterenol. At least 10 min preincubation was required to show irreversibility. Alprenolol, under the same preincubation conditions, was unable to inhibit amylase release. BrAlpM inhibited the binding of [3H]dihydroalprenolol to parotid beta adrenoreceptors over a concentration range similar to that required for inhibition of protein secretion. Cells incubated in the absence or presence of BrAlpM displayed a comparable morphologic appearance when viewed by light and electron microscopy. The degree of inhibition of isoproterenol-induced exocytosis of secretory granules by BrAlpM appeared to vary from cell to cell. These findings suggest that BrAlpM should be a useful probe to study beta adrenoreceptor function and metabolism in rat parotid acinar cells. |
| Databáze: |
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