Characterization of 3H-N-methylscopolamine binding to intact rat thymocytes.
The binding parameters of muscarinic antagonists in intact rat thymocytes were determined from competitive binding experiments with 3H-N-methylscopolamine (3H-NMS). The muscarinic antagonists inhibited binding of 3H-NMS in a dose-dependent manner. Non-linear regression analysis of the displacement curves indicated the presence of two affinity states for the muscarinic compounds. The beta-blocking agents R-propranolol, S-propranolol and alprenolol inhibited the binding of 3H-NMS to one, low affinity binding site on rat thymic lymphocytes. The ganglionic blocking substance hexamethonium did not affect the binding of 3H-NMS. The results indicate the presence of two binding sites for the radioligand on rat thymocytes, of which only one is specific for muscarinic receptor antagonists.
Rinner
I
I
Institute of Functional Pathology, University of Graz, Austria.
Porta
S
S
Schauenstein
K
K
D000818:Animals; D001665:Binding Sites / Q000502:physiology; D019832:N-Methylscopolamine; D010276:Parasympatholytics / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011976:Receptors, Muscarinic / Q000378:metabolism; D012602:Scopolamine Derivatives / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism*; D014316:Tritium
D010276:Parasympatholytics; D011976:Receptors, Muscarinic; D012602:Scopolamine Derivatives; D014316:Tritium; D019832:N-Methylscopolamine