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 ...

Histamine (10-7 to 10-4 M) concentration-dependently stimulated the production of IL-18 and IFN-gamma and inhibited the production of IL-2 and IL-10 in human PBMCs. Histamine in the same concentration range did not induce the production of IL-12 at all. The stimulatory or inhibitory effects of histamine on cytokine production were all antagonized by H2 receptor antagonists ranitidine and famoti...

The histaminergic system influences various activities of the central nervous system, including cardiovascular regulation. Histamine administered intracerebroventricularly (i.c.v.) in anesthetized rats produces the increase in mean arterial pressure (MAP) and heart rate (HR), however, in contrast to normotensive animals, histamine-induced rises in MAP and HR in critically hypotensive animals ar...

The role of the basolateral amygdala (BLA) in the consolidation of aversive memory is well established. Here we investigate the involvement of the histaminergic system in BLA on this variable. Rats were chronically implanted with bilateral cannulae in the BLA and after recovery were trained in a one-trial step-down inhibitory avoidance task. Immediately after training histaminergic compounds ei...

Histamine is well known for its roles in allergic diseases and anaphylaxis through H(1)-receptor stimulation. The H(1)-receptor stimulation by histamine results in an increase in vascular permeability, vasodilatation, and stimulation of nerve terminals in primary sensory neurons, thereby accelerating the inflammatory responses. On the other hand, histamine has been demonstrated to be involved i...

The histamine H3 receptor (H3R) has been recognized as a promising target for the treatment of various central and peripheral nervous system diseases. In this study, a non-imidazole compound, ZEL-H16, was identified as a novel histamine H3 receptor agonist. ZEL-H16 was found to bind to human H3R with a Ki value of approximately 2.07 nM and 4.36 nM to rat H3R. Further characterization indicated ...

BACKGROUND H2-histamine receptors mediate a wide range of physiological functions extending from stimulation of gastric acid secretion to induction of human promyelocyte differentiation. We have previously cloned the H2-histamine receptor gene and noted that only three amino acids on the receptor were sufficient to define its specificity and selectivity. Despite only modest overall amino acid h...

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...

The effects of external divalent cations on drug-receptor interaction were examined using guinea pig taenia. The effects of histamine on membrane potential of taenia in various solutions were also examined using the sucrose gap method. Ca2+ and Me2+ played an important role in the combination of histamine with its receptor. Sr2+, Mn2+ and Co2+ do not substitute for. Ca2+ and Me2+ in this intera...