JPET

Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Hensler, J. G.
Right arrow Articles by Frazer, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Hensler, J. G.
Right arrow Articles by Frazer, A.

Serotonergic neurons do not influence the regulation of beta adrenoceptors induced by either desipramine or isoproterenol

JG Hensler, GA Ordway, C Gambarana, P Areso and A Frazer

Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia.

It has been suggested that 5-hydroxytryptamine (serotonin)-containing neurons influence the regulation of central beta adrenoceptors caused by antidepressants. [3H]Dihydroalprenolol ( [3H] DHA) was the radioligand used in these previous studies to measure beta adrenoceptors. In this study, we compared the binding characteristics of [3H]DHA with those of [125I]iodopindolol ( [125I]PIN) and used [125I]IPIN to study effects of lesioning serotonergic nerves on the regulation of beta adrenoceptors. A comparison was made in homogenates prepared from rat frontal cortex of the specific binding of [3H]DHA with that of [125I]IPIN to beta adrenoceptors. Nonlinear regression analysis of saturation experiments of [3H]DHA binding to cortical homogenates indicated that a two-component binding model fit the data significantly better than a one-component model. A dissociation constant value of 0.47 +/- 0.16 nM and a Bmax value of 62 +/- 7 fmol/mg protein were obtained for the high-affinity site. The low-affinity site was poorly defined. Rosenthal transformations of the saturation isotherms for [3H]DHA binding were clearly curvilinear. By contrast, nonlinear regression analysis of saturation experiments of the binding of [125I]IPIN indicated that the binding of this radioligand was described adequately by a one-component model and yielded a dissociation constant value of 147 +/- 10 pM with a Bmax of 80 +/- 5 fmol/mg protein. Rosenthal transformations of the [125I]IPIN data were linear. From such data, it was inferred that [3H]DHA binds to some site in addition to beta adrenoceptors, whereas [125I]IPIN does not.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume 256, Issue 2, pp. 656-664, 02/01/1991
Copyright © 1991 by American Society for Pharmacology and Experimental Therapeutics






Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
All ASPET Journals Molecular Pharmacology Pharmacological Reviews
Molecular Interventions Drug Metabolism and Disposition

Copyright © 1991 by the American Society for Pharmacology and Experimental Therapeutics.