| Autor: |
Scheltdorf M; Lilly Research Laboratories, Department of Pharmacology, Essener Strasse 93, 22419 Hamburg, Germany., Mest HJ |
| Jazyk: |
angličtina |
| Zdroj: |
Naunyn-Schmiedeberg's archives of pharmacology [Naunyn Schmiedebergs Arch Pharmacol] 2002 Sep; Vol. 366 (3), pp. 204-8. Date of Electronic Publication: 2002 Jul 05. |
| DOI: |
10.1007/s00210-002-0612-4 |
| Abstrakt: |
Several alpha(2)-adrenoceptor agonists containing an imidazoline moiety inhibit insulin secretion when applied to beta cells. In the present study we investigated such imidazolines in regard to membrane potential effects in MIN 6 cells. We confirmed the inhibition of insulin release as reported in previous studies and showed an additional hyperpolarizing activity of the imidazolines using bisoxonol for membrane potential measurements. Pertussis toxin pre-incubation of MIN 6 cells converted the inhibitory imidazoline activity with regard to insulin release into a stimulatory effect. In addition, the marked hyperpolarization caused by the alpha-adrenoceptor agonists containing an imidazoline moiety was converted into a depolarizing effect after pertussis toxin pre-incubation. Adrenaline, an alpha-adrenoceptor agonist lacking an imidazoline moiety, also inhibited insulin release and hyperpolarized MIN 6 cells. Pertussis toxin pre-incubation led only to a loss of the inhibitory adrenaline effect and of the hyperpolarization but not to the stimulatory effects observed with the imidazolines. Thus a stimulatory effect of alpha-adrenoceptor agonists containing an imidazoline moiety was demasked by PTX in this study. It remains to be clarified to which extent a blockade of K(ATP) channels is responsible for this effect. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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