Histamine membrane receptors are defined as either H1 (blocked by diphenhydramine-like antagonists) or H2 (blocked by cimetidine-like agents). We now report the solubilization, separation, and partial characterization of specific H1 and H2 membrane receptors from calf thymocytes. Membrane fragments were incubated with [3H]histamine either alone or with unlabeled histamine, diphenhydramine, or c...

The effects of histamine H2-receptor antagonists, alone or in a combination with bismuth, on *OH-provoked degradation of deoxyribose were studied. The histamine H2-receptor antagonists (cimetidine, ranitidine and roxatidine), themselves decreased the deoxyribose damage in Fenton-type systems. In combinations with bismuth, their inhibitory effect in Fenton system (Fe(III)/ascorbic acid + H2O2 wa...

The effects of a cow's milk diet on receptor activity and histamine metabolism in gastric glands and mucosa isolated from adult rats were examined. The milk diet was associated with (1) a decreased mobilization of H2 receptors by histamine and (2) an increased mobilization of PGE2 (prostaglandin E2) receptors in mucous cells (cytoprotective effect) and parietal cells (antiacid effect). These ch...

It is increasingly clear that histamine mediates a variety of lymphocyte functions. Further understanding of these mechanisms requires a method for the analysis of histamine membrane receptors on the lymphocyte surface. We report now a biochemical technique for the identification and quantitation of specific histamine H1 and H2 receptors of lymphocytes. The method can be performed on small numb...

Few drugs have so rapidly gained an established place in modern medicine as the histamine H, receptor antagonists. As a result of the inventiveness of James Black and his colleagues, the theoretical concept of a second class of histamine receptors became a therapeutic reality. The failure of classic antihistamine drugs (more appropriately H1 receptor antagonists) to block the actions of histami...

conclusions cyclosom and histamine synergistically exert catalepsy in old rats. in light of these data, the combination of the decreased brain level of somatostatin and increased brain level of histamine may be of pathogenic relevance for extrapyramidal signs in pd. results cyclosom (0.2, 1.0, and 5.0 µg) and histamine (1.0 and 10.0 µg) alone were ineffective in both young and old animals. in c...

It has been well established that cardiac actions of histamine are mediated by histamineHI and H2 receptors and that there exist specific agonists and antagonists acting on them (1.2.3:4.5.7.8 and 11). Cyclizine. an antihistamine has been shown to antagonize positivechronotropic effect of histamine which is mediated through H2 receptors (8) and to possessantiarrhythmic effect in experiernntal c...

Histamine and histamine receptors in the central nervous system actively participate in the modulation of motor control. In clinic, histamine-related agents have traditionally been used to treat vestibular disorders. Immunohistochemical studies have revealed a distribution of histaminergic afferents in the brainstem vestibular nuclei, including the lateral vestibular nucleus (LVN), which is cri...

Recent studies indicate that the secretagogue action of histamine on the salivary gland is mediated via H2-receptors. In this study we attempt to characterize the histamine H2-receptors in the submandibular gland of the rat. The results show the presence of a specific 3H-cimetidine binding site in the gland. However, the binding constants of this site are not fully characteristic of the specifi...

IL-12 and IL-10, respectively, stimulate Th1 and Th2 immune responses. The development of some allergic reactions, infections, and tumors are associated with excessive histamine production and a shift toward Th2 responses. Here we address the possibility that this association is causally linked, at least in part, to modulation of IL-12 and IL-10 production by histamine. We report that histamine...