These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: Influence of pH on the binding of scopolamine and N-methylscopolamine to muscarinic receptors in the corpus striatum and heart of rats.
    Author: Ehlert FJ, Delen FM.
    Journal: Mol Pharmacol; 1990 Jul; 38(1):143-7. PubMed ID: 2370852.
    Abstract:
    The influence of pH on the binding of scopolamine and [3H]N-methylscopolamine to muscarinic receptors in the heart and corpus striatum was investigated. The specific binding of [3H]N-methylscopolamine in the heart and corpus striatum was relatively insensitive to pH over the range of 6 through 10 but decreased markedly below pH 6.0. This reduction in binding was attributed to a reversible decrease in the observed affinity without an effect on the binding capacity. The data are consistent with the postulate that [3H]N-methylscopolamine competes with hydrogen ions for an acidic group on the muscarinic receptor that has a pKA of approximately 5.5 in both the heart and corpus striatum. When measured by competitive inhibition of the binding of [3H]N-methylscopolamine, the affinity of scopolamine decreased relative to that of [3H]N-methylscopolamine as the pH increased from 6 to 10, confirming that it is primarily the protonated form of scopolamine that binds with muscarinic receptors.
    [Abstract] [Full Text] [Related] [New Search]