The role of the nucleus basalis magnocellularis (NBM) in fear conditioning encoding is well established. In the present report, we investigate the involvement of the NBM histaminergic system in consolidating fear memories. The NBM was injected bilaterally with ligands of histaminergic receptors immediately after contextual fear conditioning. Histaminergic compounds, either alone or in combinati...

The aim of the present study was to determine the effect of the histaminergic precursor L-histidine and the H3 receptor antagonist thioperamide on the learning process of zebrafish submitted or not to confinement stress. On each of the 5 consecutive days of experiment (D1, D2, D3, D4, D5), animals had to associate an interruption of the aquarium air supply with food offering. Non-stressed zebra...

In the present study, we investigated the effects of histamine and its specific H(1), H(2) and H(3) receptor blockers in cerebellar granular cell culture derived from rat pups. Histamine was applied at 10(-9),10(-8), 10(-7),10(-6), and 10(-5) M for 16 h into the cultures and the highest dose was found to be the most toxic one. Pheniramine (H(1) receptor blocker), ranitidine (H(2) receptor block...

Helicobacter pylori may increase or inhibit gastric acid. We studied acid variations and plasma gastrin in cats harboring Helicobacter felis, harboring H. pylori, or free of gastric pathogens with reference to thioperamide (H(3) receptor antagonist) and SR-27417A (PAF receptor antagonist). In cats harboring H. felis, gastric mucosa were histologically normal. After H. felis eradication, pentaga...

Hydrogen is often present in metals as a result of production, fabrication and processing operations or service conditions. Thus, it can be regarded as an alloying element. Although, high hydrogen levels in metals can have a devastating effect on the mechanical properties, many positive effects can also be derived from its high solubility. The objective of this paper is to review some positive ...

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Histamine H3 receptors are autoreceptors that regulate histamine release from histaminergic neuronal terminals. The cerebral cortex, including the insular cortex (IC), expresses abundant H3 receptors; however, the functions and mechanisms of H3 receptors remain unknown. The aim of this study was to elucidate the functional roles of H3 in synaptic transmission in layer V of the rat IC. Unitary e...

The histamine H3 receptor agonist (R)alpha-methylhistamine (MeHA) inhibited, in a nanomolar range, basal and carbachol-stimulated inositol phosphate formation in the human gastric tumoral cell line HGT1-clone 6. The inhibition was reversed by micromolar concentrations of the histamine H3 receptor antagonist thioperamide and was sensitive to cholera or pertussis toxin treatment. Using [3H]N alph...