Specific binding of 3H-tiotidine to histamine H2 receptors in guinea pig cerebral cortex

Abstract

Although the H2 subclass of histamine receptor has been revealed by classical pharmacological approaches, the direct identification of this adenylate cyclase-linked receptor has, despite much effort, remained elusive. Initial studies using 3H-metiamide and 3H-histamine and, subsequently, work from our own laboratory and others using 3H-cimetidine and 3H-ranitidine in various tissues, has shown the unsuitability of these ligands for labelling the H2 receptor. We report here our results using 3H-tiotidine, a more potent H2-antagonist than either cimetidine or ranitidine, and show that this ligand meets the criteria for labeling the H2 receptor in guinea pig cerebral cortex membranes.

Histamine Receptors Mediating a Positive Inotropic Effect in Guinea Pig and Rabbit Ventricular Myocardium: Distribution of the Receptors and Their Possible Intracellular Coupling Processes

“…The specific binding for [3H]tiotidine accounted routinely for 20% or less in both species. The relatively large por tion of the nonspecific component for this ligand has been reported in previous studies on guinea pig cerebral cortex (25) and guinea pig lung parenchyma (26). The equilib rium dissociation constant (KD) and the maximal binding capacity (Borax) were calculated from plots according to the method of Scatchard (27).…”

KW‐3902, a selective high affinity antagonist for adenosine A1 receptors

“…The DNA sequence obtained was confirmed to be the sequence as reported. The cDNA was inserted into the expression vector pAGE I10, a dhfr transcription unit containing a version of pAGE107 (Miyaji et al, 1990 Binding of various radioligands [3H]-ketanserin, and [3H]-quipadine to the adenosine transporters (Verma & Marangos, 1985), to a,-and Ox2-adrenoceptors (Greenberg et al, 1976), ,B-adrenoceptors (U' Prichard et al, 1978), benzodiazepine receptors (Braestrup & Squires, 1977), dopamine DI receptors (Billard et al, 1984), dopamine D2 receptors (Leysen & Gommeren, 1981), GABAA receptors (Williams & Risley, 1979), histamine H, receptors (Chang et al, 1979), histamine H2 receptors (Gajtkowski et al, 1983), muscarinic Ml acetylcholine receptors (Bloom et al, 1987), nicotinic acetylcholine receptors (Lippiello & Fernandes, 1988), 5-HTA receptors (Gozlan et al, 1983), 5-HT2 receptors respectively, were measured according to the methods described previously.…”

A study of the H2‐receptor for histamine stimulating adenylate cyclase in homogenates of guinea‐pig lung parenchyma

“…Similarly, metiamide was found to inhibit histamine-stimulated adenylate cyclase in gastric mucosa (Rouff & Sewing, 1975). More recently, inhibition by several H2-antagonists has been studied using histamine-stimulated adenylate cyclase in gastric mucosa, and the affinities of the antagonists for the receptor mediating adenylate cyclase activation correlate well with the affinities of these drugs obtained in other biochemical and pharmacological studies of these receptors (Gajtkowski et al, 1983).…”