The aim of the present study was to investigate whether and by which mechanism; histamine can induce state-dependent retrieval of passive avoidance task. The pre-training or pre-test intracerebroventricular (i.c.v.) injection of histamine (20µg/mouse) impaired retrieval, when it was tested 24 h later. In the animals, which retrieval was impaired due to histamine pre-training administration, pre...

The types and functions of histamine receptors in the submucosal arterioles of the corpus and antrum of the cat and rat stomach were studied using an in vivo microscopy technique. Change in arteriolar diameter in response to superfusion of histamine with and without antagonists was measured by an image-splitting technique. H1 and H2 histamine receptors subserving vasodilatation were demonstrate...

Whole cell perforated patch-clamp methods were used to investigate ionic mechanisms underlying histamine-evoked excitatory responses in small intestinal AH-type myenteric neurons. When physiological concentrations of Na(+), Ca(2+), and Cl(-) were in the bathing medium, application of histamine significantly increased total conductance as determined by stepping to 50 mV from a holding potential ...

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...

Systemic and pulmonary hemodynamic responses to histamine were investigated inchronically instrumented unanesthetized nonpregnant ewes. Histamine was administered intravenously and into the pulmonary artery. The effects of the same doses of histamine were assessed following H1 and H2 receptor blockade. The effects ocular changes were also monitored. Results indicate that intravenous histamine p...

Histamine H(3) receptors inhibit the release of not only histamine itself, but also other neurotransmitters including dopamine. Previous papers have reported that histaminergic neurons inhibit psychostimulant-induced behavioral changes. To examine whether deficiency in histamine H(3) receptors influences psychostimulant-induced behavioral sensitization and reward, we examined locomotor activity...

Histamine affects pancreatic secretion, but its direct action on ion transport by pancreatic duct epithelial cells (PDEC) has not been defined. We now characterize the secretory effects of histamine on cultured, well-differentiated, and nontransformed dog PDEC. Histamine stimulated, in a concentration-dependent manner (1-100 μM), a cellular125I-efflux that was inhibited by 500 μM 5-nitro-2-(3-p...

OBJECTIVE Histamine and histamine receptors are found in atherosclerotic lesions, and their signaling and subsequent proatherogenic or proinflammatory gene expression are involved in atherogenesis. In the present study, we generated apolipoprotein E (apoE) and histamine synthesizing histidine decarboxylase double knockout (DKO) mice on a C57BL/6J (wild-type mice) background to clarify the roles...

In human aortic smooth muscle cells, prostaglandin E2 (PGE2) stimulates adenylyl cyclase (AC) and attenuates the increase in intracellular free Ca concentration evoked by activation of histamine H1 receptors. The mechanisms are not resolved. We show that cAMP mediates inhibition of histamine-evoked Ca signals by PGE2. Exchange proteins activated by cAMP were not required, but the effects were a...

Histamine is involved in a variety of physiologic responses, such as inflammation, type I allergy, gastric acid secretion, and neurotransmission. Previous studies have focused on specific receptors for histamine and histamine release through degranulation, and the regulation of histamine synthesis and its physiologic roles remain to be clarified. We have studied histidine decarboxylase (HDC), t...