G-protein-coupled receptors (GPCRs) represent the largest family of receptors involved in transmembrane signaling. Although these receptors were generally believed to be monomeric entities, accumulating evidence supports the presence of GPCRs in multimeric forms. Here, using immunoprecipitation as well as time-resolved fluorescence resonance energy transfer to assess protein-protein interaction...

Astemizole and terfenadine, two potent non-sedative H1 antihistamines, had no effect on itch measured objectively as nocturnal scratching and subjectively on a 10 cm line. Trimeprazine, however, a more sedative but less potent H1 antihistamine, was antipruritic, as was nitrazepam, a sedative benzodiazepine. We concluded (a) that antipruritic drugs act centrally by a property related to sedation...

Parched and ground whole garden slugs are claimed in rural Jamaican folklore practices to have useful effects in the treatment of bronchial asthma. Since this claim may be associated with respiratory dysfunction due to histamine from allergic sensitization, the authors investigated the effects of a semi-pure alcoholic extract (AST-1) on histamine-induced contraction of the guinea pig in vitro t...

Muscarinic action of acetylcholine was demonstrated in the human isolated appendix. Histamine-induced contractions seemed to the mediated by H1 receptors. Nicotine and DMPP-induced contractions were mediated through their action on ganglion cells. Experiments with adrenergic drugs suggested the presence of beta receptors.

objective: crocin, as an active constituent of saffron, has many biological functions including antioxidant and anti-inflammatory activities. the present study was aimed to investigate the effects of crocin and chlorpheniramine on local edema induced by histamine. materials and methods: local edema was induced by subcutaneous injection of histamine (100 μl, 0.1%) in ventral surface of right hin...

It has long been recognised that mast cells and basophils are prominent sources of preformed histamine in humans and that this biogenic amine serves as one of the most important inflammatory mediators. In allergic diseases, histamine has previously been shown to partially modulate symptoms such as airway obstruction, mucus secretion, reddening of the skin and itch, all of which were attributed ...

The eye is a target organ for the action of several topical or systemic drugs. The aim of the present study is to analyze the differences in reactivity between the iris and conjunctiva vessels after the topical administration of histamine and histamine receptor blockers respectively. Using a novel non-invasive technique for the quantification of the vascular diameters in the eye vessels, the re...

To evaluate the ability of histamine to induce ventricular arrhythmias, we studied the effects of histamine on ventricular rhythmicity in the isolated guinea pig heart with complete atrioventricular conduction block. As a function of dose (0.1-30 microgram), histamine enhanced the idioventricular rate by increasing the rate of firing of the original pacemaker and also by causing the sudden appe...

We studied the pharmacological characteristics of HSR-609 (3-[4-(8-fluoro-5,11-dihydrobenz[b]oxepino[4,3-b]pyridin-11- ylidene)- piperidino]propionic acid dihydrate), a novel amphoteric antiallergic agent, on the central nervous system (CNS). Its selectivity for the histamine H1-receptor and its ability to penetrate into the CNS were compared with those of typical antiallergic agents and the no...