| Autor: |
Manier DH; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232., Bieck PR, Duhl DM, Gillespie DD, Sulser F |
| Jazyk: |
angličtina |
| Zdroj: |
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology [Neuropsychopharmacology] 1992 Sep; Vol. 7 (2), pp. 105-12. |
| Abstrakt: |
The beta-adrenoceptor-coupled adenylate cyclase system in rat C6 glioma cells displays many characteristics observed in brain tissue: using nonlinear regression analysis of agonist competition binding curves, we demonstrated that the bulk of beta-adrenoceptors show high nanomolar affinity for isoproterenol; like in brain tissue, Gpp(NH)p does not shift agonist competition binding curves to the right; and the agonist isoproterenol rapidly downregulates the number of beta-adrenoceptors and deamplifies the norepinephrine signal. However, unlike in brain tissue, where (-)-oxaprotiline fails to decrease the number of beta-adrenoceptors and to desensitize the cyclic adenosine monophosphate generating system, it desensitizes the beta-adrenoceptor-coupled adenylate cyclase system in C6 glioma cells. Determination of the relative steady-state levels of beta-adrenoceptor messenger ribonucleic acid (mRNA) by Northern blot analysis showed a twofold increase in the steady-state levels of the mRNA at 30 minutes following exposure to (-)-isoproterenol or (-)-oxaprotiline. At 48 hours, basal values of mRNA were observed at a time when beta-adrenoceptors were maximally decreased. Further experiments on transcriptional activation, and mRNA stability and translation will be required to unravel the complexity of agonist-dependent and agonist-independent regulation of beta-adrenoceptor density and function. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
