René Hammer

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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)
Inhaled antimuscarinics, often called anticholinergics in clinical medicine, are established as first line bronchodilators in COPD. Tiotropium has been developed as a new generation antimuscarinic following ipratropium. Tiotropium is a specific, highly potent antimuscarinic, demonstrating very slow dissociation from muscarinic receptors. Dissociation from(More)
A pharmacological classification of receptor-activated nonselective cation channels has not been possible because of the lack of specific and potent pharmacological blockers. In dibutyryl-cAMP-differentiated HL-60 cells, we recently identified ATP- and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-stimulated cation currents that were blocked by an(More)
The heterogeneity of muscarine receptors was examined in two brain regions (cerebral cortex and cerebellum) and in some parasympathetically innervated peripheral tissues (heart, salivary gland and intraorbital lacrimal gland), by in vitro binding techniques. As a tool, we used a new antimuscarinic compound, AF-DX 116 (see text for structural formula and(More)
The specific binding to alpha-adrenoceptors in crude plasma membrane preparations of the rat brain was studied by means of 3H-clonidine (specific radioactivity 26.7 Ci/mmole). Equilibrium binding of 3H-clonidine could be described adequately according to a two-site model with a minor population of high affinity sites (KD1 = 0.4 nM) and a major population of(More)
Muscarinic receptor subtypes in longitudinal and circular smooth muscles of the guinea pig ileum were characterized with the use of the cardioselective antagonist AF-DX 116 in binding competition experiments against 0.3 nM [3H] N-methylscopolamine [( 3H]NMS). This compound recognized a heterogeneous receptor population in both smooth muscles, revealing the(More)
In vitro competition binding experiments with the selective muscarinic antagonists AF-DX 116 and pirenzepine (PZ) vs 3H-N-methylscopolamine as radioligand revealed a characteristic distribution of muscarinic receptor subtypes in different regions of rat brain. Based on non linear least squares analysis, the binding data were compatible with the presence of(More)
Using the classical muscarinic antagonist 3H-N-methyl-scopolamine as radioligand and unlabelled pirenzepine (PZ) as displacing agent, a heterogeneous muscarinic receptor population consisting of about 70% M1-receptors and 30% M2-receptor, can be demonstrated in crude membranes of calf sympathetic ganglia. In the same preparation only low and variable(More)