Histamine covalently bound to glutaraldehyde-activated ferritin was prepared as either monomers or as small aggregates of approximately 0.05 to 0.15 micrometer Diam, suitable for electron microscopic detection of histamine cellular binding sites. The histamine-ferritin conjugates (MF) maintain the histamine capability to induce the opening of endothelial junctions in venules. To investigate the...

Effects of histamine (HA) and agonists of HA receptors on phosphoinositide metabolism in chick cerebral cortex have been studied using two approaches – measurement of inositol 1,4,5-trisphosphate (IP ) level by a specific and sensitive IP receptor radioassay, and analysis of [ H]inositol phosphates accumulation in cortical slices prelabeled with myo-[ H]inositol. HA concentration-dependently el...

The M-type potassium channel, of which its molecular basis is constituted by KCNQ2-5 homo- or heteromultimers, plays a key role in regulating neuronal excitability and is modulated by many G protein-coupled receptors. In this study, we demonstrate that histamine inhibits KCNQ2/Q3 currents in human embryonic kidney (HEK)293 cells via phosphatidylinositol 4,5-bisphosphate (PIP(2)) hydrolysis medi...

OBJECTIVES Experiments were designed to determine if salivary gland homogenates (SGH) of the sand fly Lutzomyia longipalpis, the vasodilatory peptides maxadilan and pituitary adenylate cyclase-activating peptide (PACAP-38) may cause plasma leakage and to what extent these effects could be due to PAC1 receptor stimulation. METHODS Using FITC-dextran as a plasma marker, intravital microscopy of...

A radioreceptor assay (RRA) for the quantitative determination of a new antiallergic agent, 1(2-ethoxyethyl)-2-(4-methy1-1-homopiperazinyl)benzimidazole difumarate (KB-2413), has been developed. This RRA method, based upon competitive binding of [3H]mepyramine and KB-2413 to histamine H, receptors in guinea pig cerebellum, allows the simple, sensitive and reproducible determination of KB-2413 i...

An LC-MS method is described for the determination of the synthetic reagent N,N-dimethylaminoethyl chloride (DMC) in the drug substance diltiazem hydrochloride, for which the permissible limit is not more than 1 ppm (microgram g-1). The N,N-dimethylaziridinium ion (DMA), the reactive intermediate formed by cyclisation of DMC, is also detected. A column switching arrangement is used: diltiazem h...

In rats, the hypothalamic neurotransmitter histamine participates in regulation of vasopressin secretion and seems to be of physiological importance, because blockade of the histaminergic system reduces dehydration-induced vasopressin secretion. We investigated whether histamine is also involved in regulation of vasopressin secretion during dehydration in humans. We found that 40 h of dehydrati...

INTRODUCTION AND OBJECTIVES Asthma is one of the most prevalent chronic diseases with effective treatment in paediatrics. The aim of this study is to describe the paediatric prescribing of anti-asthmatics in Castilla-León, analyzing its geographic variability and temporal evolution. MATERIAL AND METHODS An analysis was made of prescriptions dispensed in pharmacies of R03 therapeutic subgroup ...

We investigated morphological alterations induced by s.c. injection of 2.5 microg of Bothrops jararaca venom in rats. Intense disorganisation of collagen fibres was observed 1 min after the venom injection, particularly at regions near vessels and nerves. Mast cells were degranulated, and erythrocytes were seen leaving venules throughout the endothelial junctions. At this time, damaged endothel...

the effect of repetitive electrical field stimulation and the response of the guinea-pig and rat ileal longitudinal muscle to single pulse stimulations was examined. single pulse field stimulation produced twitch contraction which was inhibited by repetitive field stimulation (10 hz, 40v, 0.5 msec for 5 m). this inhibition was largely, though never completely, reversed by naloxone. contractions...