Search results for "Histamine receptor"

2020

Many patients regularly take histamine receptor antagonists, such as cetirizine, to prevent allergic reactions, but these antiallergic drugs may have inadvertent effects on orthodontic treatment. In previous studies, histamine has been shown to modulate the sterile inflammatory reaction underlying orthodontic tooth movement. Pertinent effects of histamine antagonization via cetirizine during orthodontic treatment, however, have not been adequately investigated. We thus treated male Fischer344 rats either with tap water (control group) or cetirizine by daily oral gavage corresponding to the clinically used human dosage adjusted to the rat metabolism (0.87 mg/kg) or to a previously published …

2020

As type-I-allergies show an increasing prevalence in the general populace, orthodontic patients may also be affected by histamine release during treatment. Human periodontal ligament fibroblasts (PDLF) are regulators of orthodontic tooth movement. However, the impact of histamine on PDLF in this regard is unknown. Therefore PDLF were incubated without or with an orthodontic compressive force of 2g/cm2 with and without additional histamine. To assess the role of histamine-1-receptor (H1R) H1R-antagonist cetirizine was used. Expression of histamine receptors and important mediators of orthodontic tooth movement were investigated. PDLF expressed histamine receptors H1R, H2R and H4R, but not H3…

Effect of histamine and histamine analogues on human isolated myometrial strips.

1992

1. The effect of histamine and histamine H1- and H2-receptor agonists on isolated myometrium strips of premenopausal women has been examined. The effect of acetylcholine was also determined. 2. Histamine, 2-pyridylethylamine, 4-methylhistamine and acetylcholine, but not dimaprit, produced a concentration-related contractile response in human isolated myometrial strips. Histamine also produced a further contraction in human isolated myometrial strips precontracted with KCl (55 mM). 3. The contractile response to histamine was antagonized by the histamine H1-receptor antagonist, clemizole (0.1 microM) but was potentiated by the histamine H2-receptor antagonist, ranitidine (10 microM). Clemizo…

Influence of hormonal treatment on the response of the rat isolated uterus to histamine and histamine receptor agonists.

1992

The response of the isolated uterus to histamine and histamine agonists was investigated in progesterone- and oestrogen-treated rats. The uterine inhibitory responses to histamine and 4-methylhistamine (a histamine H2 receptor agonist) were similar in KCl-contracted uteri from progesterone- and oestrogen-treated rats. The histamine H1 receptor agonist, 2-pyridyl-ethylamine, produced a relaxant response only in progesterone dominant uterus. This was inhibited by the histamine H1 receptor antagonist. In the rat isolated uterus which was not preconstricted by KCl, neither histamine, 4-methylhistamine, nor 2-pyridyl-ethylamine produced any effect in the presence or absence of ranitidine. Raniti…

Models with clinically-relevant and life-threatening histamine-related cardiovascular disturbances: Evaluation of the clinical effectiveness of H1/H2…

1996

Histamine binding to H2 receptors stimulates phospholipid methylation in mast cells

1982

Rat peritoneal mast cells incubated in vitro in the presence of L-[methyl-3H] methionine and exposed to histamine undergo a rapid but transient increase in phospholipid methylation. By using specific H1- and H2-receptor antagonists, and histamine analogues differing in their H2-receptor agonist potency, it has been demonstrated that this metabolic event is dependent on histamine binding to H2-receptors.

Effects of histamine on spontaneous electrical activity of neurons in rat suprachiasmatic nucleus

1991

Abstract The hypothalamic suprachiasmatic nucleus (SCN) is thought to be a light-entrained pacemaker in mammals, inducing a wide range of endogenous circadian events. In rat brain, histaminergic (HAergic) fibres are particulary rich in the hypothalamus. This prompted an investigation of the influence of bath-applied HAergic compounds on the spontaneous electrical activity of SCN neurons, recorded extracellularly in the hypothalamic slice preparation. Cells activated by bath application of HA ( n = 28) outnumbered those inhibited by HA ( n = 6). 48% of cells tested ( n = 28) were unresponsive to HA application. HA-induced activation of SCN neurons' discharge rate could be suppressed by the H…

The effects of LSD in the guinea-pig ileum

1985

The effects of lysergic acid diethylamide (LSD) on acetylcholine release and on smooth muscle tone were studied in the myenteric plexus-longitudinal muscle preparation of the guinea pig. LSD (0.01-10 microM) depressed in a concentration-dependent manner the electrically-evoked [3H]-acetylcholine outflow from strips preincubated with [3H]-choline. The maximal effect was a 45% inhibition by 1 microM LSD. The spontaneous outflow was not affected. Metitepine competitively antagonized (pA2 8.0) the LSD-induced reduction of the evoked outflow. Tolazoline and mepyramine did not affect the inhibitory action of LSD. The contractions in response to electrical stimulation were enhanced by 34% in the p…

Modulatory effects of the serotonergic and histaminergic systems on reaction to light in the crustacean Gammarus pulex

2013

Serotonin modulates reaction to light in many animals. In the freshwater amphipod Gammarus pulex, exogenous administration of serotonin induces a transient reversal of photic behaviour from strong photophobia to photophily. We have elucidated further the neuromodulation of photic behaviour in G. pulex by using in vivo pharmacology and behavioural testing. Using several mammalian 5-HT receptor antagonists and agonists, we provide evidence for a role of serotonin receptors in the 5-HT-dependent regulation of G. pulex photic behaviour, possibly involving 5-HTR2 subtype. Serotonin-induced photophily was blocked by the 5-HT receptor antagonists, mianserin, cyproheptadine, and ritanserin, but not…

Synthesis and Characterization of New Bivalent Agents as Melatonin- and Histamine H3-Ligands

2014

Melatonin is an endogenous molecule involved in many pathophysiological processes. In addition to the control of circadian rhythms, its antioxidant and neuroprotective properties have been widely described. Thus far, different bivalent compounds composed by a melatonin molecule linked to another neuroprotective agent were synthesized and tested for their ability to block neurodegenerative processes in vitro and in vivo. To identify a novel class of potential neuroprotective compounds, we prepared a series of bivalent ligands, in which a prototypic melatonergic ligand is connected to an imidazole-based H3 receptor antagonist through a flexible linker. Four imidazolyl-alkyloxy-anilinoethylami…