In a cell-free system prepared from guinea pig gastric mucosa, histamine and Nalpha-methyl-histamine produced dose-dependent stimulation of cyclic AMP formation and 1,4-methylhistamine had a minimal stimulatory effect. N-methyl-N'-(2-[5-methylimidazole-4-yl-methylthio]-ethyl) -thiourea (metiamide), a new H2 receptor inhibitor, selectively blocked the stimulation of adenylate cyclase by histamin...

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a member of the scavenger receptor family, and is known to be expressed in monocytes/macrophages. We investigated the effect of histamine on the expression of LOX-1 in cells of the human monocytic leukemia cell line THP-1. Histamine as well as forskolin and dibutyryl cyclic AMP (Bt2-cAMP) stimulated the THP-1 monocytes to expres...

Radial artery (RA) bypass grafts can develop severe vasospasm. As histamine is known to induce vasospasm, its effect on RA was assessed compared with the classic bypass vessels internal mammary artery (MA) and saphenous vein (SV). The vessels were examined in organ chambers for isometric tension recording. Histamine induced contractions on baseline; the sensitivity was higher in RA and SV than ...

Background: Histamine functions as a neurotransmitter in the brain. Of the 4 receptor subtypes, H2 receptors are present at high density in the thalamus, which is believed to be important in schizophrenia because of its essential role in sensory gating and attention. There is strong evidence from animal studies of a relationship between histamine and schizophrenia and more modest clinical evide...

BACKGROUND Proton pump inhibitors and histamine H2 receptor antagonists are two of the most commonly prescribed drug classes for pediatric gastroesophageal reflux disease, but their efficacy is controversial. Many patients are treated with these drugs for atypical manifestations attributed to gastroesophageal reflux, even that causal relation is not proven. OBJECTIVE To evaluate the use of pr...

background: previous investigations have revealed, cimetidine, a histamine h2-receptor antagonist, show radioprotective effects against gamma- and neutron-induced micronuclei in bone marrow erythrocytes. in this study, the anticlastogenic effects of famotidine and ranitidine, which act similar to cimetidine as histamine h2-receptor antagonists, was investigated. materials and methods : balb/c m...

Nerve growth factor (NGF) as an autocrine or paracrine growth factor plays a critical role in the pathogenesis and progression of human pancreatic cancer. NGF is synthesized as a proform (proNGF) that, when cleaved, releases mature ligand (mNGF). proNGF and mNGF bind to high-affinity tyrosine kinase receptor A (TrkA) and low-affinity receptor p75 to different extents. Histamine is a potent stim...

The histamine H2 receptor is a member of the family of G-protein-coupled receptors and is linked to the activation of adenylate cyclase phospholipase C (PLC). In this study we examined the effects of protein kinase C (PKC) activation in Chinese hamster ovary (CHO) cells stably expressing canine histamine H2 receptors. Pretreatment with 100 nM phorbol 12-myristate 13-acetate at 37 degrees C for ...

Effects of histamine per se along with its specific agonists and antagonists were studied on the skin melanophores of Hemidactylus flaviviridis to study the role of histamine receptors in pigmentation. Histamine and 2-methyl histamine induced powerful melanin aggregation effects, leading to paling of the skin through stimulation of H1 receptors. On the other hand, 4-methyl histamine, a specific...