The membrane-permeabilizing activities of mastoparans and related histamine-releasing agents were compared through measurements of K(+) efflux from bacteria, erythrocytes, and mast cells. Changes in bacterial cell viability, hemolysis, and histamine release, as well as in the shape of erythrocytes were also investigated. The compounds tested were mastoparans (HR1, a mastoparan from Polistes jad...

The release of histamine from rat tissues rich in mast cells, induced by antigen, concanavalin A, dextran, compound 48/80, A 23187, phosphatidic acid and chlortetracycline, has been compared with that from isolated peritoneal mast cells of rats. Whereas most of the agents were more active than dextran in in vitro experiments, the reverse was found when they were injected intradermally into the ...

BACKGROUND Iodinated contrast media can cause pseudoallergic reactions associated with histamine release in significant numbers of patients. To clarify whether these adverse reactions may be aggravated by a compromised histamine catabolism we asked if radiographic contrast agents in vitro inhibit the histamine inactivating enzymes diamine oxidase (DAO) and histamine N-methyltransferase (HMT). ...

The efficiency of a standardised inhalation test procedure was studied by examining the reproducibility of responses to histamine and methacholine. In addition, the responses to the two agents were compared. Each set of duplicate tests was carried out on a separate day within one week, and all factors known or presumed to influence responses were carefully controlled. The results were expressed...

The occurrence of histamine in the granules of mammalian mast cells has been established by combined bioassay and histological studies (RILEY and WEST, 1953), by chemical analysis of the granule fraction (HAGEN, BARRNETT and LEE, 1959) and further by fluorescence histochemistry for histamine (JUHLIN and SHELLEY, 1966; YAMASAKI, 1967; TAKAYA, 1969). Certain substances such as compound 48/80 (PAT...

Ethanol and other congeners in alcoholic beverages foods are known triggers of alcohol-induced headaches (AIHs). Recent studies implicate AIHs as an important underlying factor for neuroinflammation. Studies show the relationship between beverages, AIH agents, neuroinflammation, pathway they elicit. However, elucidating specific agents’ pathways scarce. Works reviewing their can give invaluable...

objective: crocin and safranal, as the major constituents of saffron, have many biological activities. this study investigated the effects of crocin and safranal on yawning response induced by intracerebroventricular (i.c.v.) injection of histamine in rats. materials and methods: in ketamine/xylazine-anesthetized rats, a guide cannula was implanted in the right ventricle of the brain and yawnin...

Barnacles are notorious marine fouling creatures; their planktonic cyprid larvae attach to material substrates and metamorphose. Histamine has shown great importance in regulating settlement metamorphosis. This study aimed investigate the mechanisms of histamine-induced larval settlement. Cyprids were exposed histamine or loratadine, an anti-histamine compound. The percent settlements histamine...

Histamine, in vitro, via H2-receptor activation, exerts an inhibitory effect on polymorphonuclear (PMN) chemotaxis and T-lymphocyte proliferation. The aim of this study was to verify these histamine inhibitory effects in man. Healthy and asymptomatic asthmatic volunteers inhaled a histamine (0.1%), methacholine (0.1%) or saline aerosol for 3 min. Asthmatics were selected on the basis of low bro...

The intravenous injection of vancomycin sometimes causes anaphylactoid reactions, in which histamine release may play a major role. These reactions are more frequently manifested when vancomycin is injected into anesthetized patients. We examined the vancomycin-induced histamine release and the interaction of vancomycin with muscle relaxants or opioid in rats. In an in vitro study with rat peri...