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Some antagonists exhibit tissue selectivity in their pharmacological antagonism of muscarinic responses. However, the affinity constants for equilibrium binding of classical antagonists to muscarinic receptors in subcellular preparations have shown only small variations in different peripheral tissues and regions of the brain. The binding curves do not(More)
The binding characteristics of muscarinic receptors have been critically examined in six regions of the rat brain. The binding curves of antagonists are similar for all six areas but the binding curves of agonists show large differences. It is shown that in all regions there are three classes of receptors with similar binding characteristics but that these(More)
The interaction of gallamine with muscarinic receptors from different tissues has been investigated. Gallamine binds to a site distinct from the conventional muscarinic ligand binding site and modulates the binding of agonists and antagonists to the conventional binding site. In agreement with reported pharmacological studies, the effects of gallamine on(More)
[3H]Propylbenzilylcholine mustard ([3H]PrBCM) is a synthetic, potent muscarinic antagonist, which binds specifically and irreversibly by means of a covalent linkage to muscarinic receptors. Ten micrometer coronal cryostat sections taken through unfixed rat brain at the level of the maximum extent of the caudate nucleus were mounted on glass slides and(More)
The ontogeny of muscarinic acetylcholine receptors in the rat brain has been examined using the radioligands, [3H]N-methylscopolamine, [3H]propylbenzilylcholine and [3H]oxotremorine-M. In the 3 regions of the brain selected for study, the cerebral cortex, the diencephalon and the medulla-pons, the receptors develop at different rates. The most rapid(More)
The antagonist and agonist binding properties of muscarinic acetylcholine receptors on membranes derived from the frog (R. temporaria) brain are very similar to those found for the muscarinic receptors of the mammalian brain. The highest concentrations of receptor are found in the optic tectum and diencephalon; the lowest levels in the hindbrain, spinal(More)
1 The binding properties of the muscarinic receptors in the ciliary muscle of cynomolgus monkeys have been evaluated. 2 The concentration of receptor binding sites is the highest yet reported. As found in many species and tissues, there are subclasses of agonist binding sites. Agonist binding is not affected by the non-hydrolysable guanosine triphosphate(More)