29 research outputs found
Differential effects of histamine H 3 receptor inverse agonist thioperamide, given alone or in combination with the N-methyl-d-aspartate receptor antagonist dizocilpine, on reconsolidation and consolidation of a contextual fear memory in mice
Full text linkChanges in the histaminergic system during vestibular compensation in the cat
No full textTo determine how the histaminergic system is implicated in vestibular compensation, we studied the changes in histidine decarboxylase (HDC; the enzyme synthesizing histamine) mRNA regulation in the tuberomammillary (TM) nuclei of cats killed 1 week, 3 weeks and 3 months after unilateral vestibular neurectomy (UVN). We also used one- and two-step bilateral vestibular neurectomized (BVN) cats to determine whether HDC mRNA regulation depended on the asymmetrical vestibular input received by the TM nuclei neurons. In addition, we analysed the HDC mRNA changes in the TM nuclei and the recovery of behavioural functions in UVN cats treated with thioperamide, a pure histaminergic drug. Finally, we quantified binding to histamine H(3) receptors (H(3)Rs) in the medial vestibular nucleus (VN) by means of a histamine H(3)R agonist ([(3)H]N-α-methylhistamine) in order to further investigate the sites and mechanisms of action of histamine in this structure. This study shows that UVN increases HDC mRNA expression in the ipsilateral TM nucleus at 1 week. This increased expression persisted 3 weeks after UVN, and regained control values at 3 months. HDC mRNA expression was unchanged in the one-step BVN cats but showed mirror asymmetrical increases in the two-step BVN compared to the 1 week UVN cats. Three weeks' thioperamide treatment induced a bilateral HDC mRNA up-regulation in the UVN cats, which was higher than in the untreated UVN group. Binding to histamine H(3)Rs in the MVN showed a strong bilateral decrease after thioperamide treatment, while it was reduced ipsilaterally in the UVN cats. That such changes of the histaminergic system induced by vestibular lesion and treatment may play a functional role in vestibular compensation is strongly supported by the behavioural data. Indeed, spontaneous nystagmus, posture and locomotor balance were rapidly recovered in the UVN cats treated with thioperamide. These results demonstrate that changes in histamine levels are related to vestibular compensation
Low-dose thioperamide injected into the cerebellar vermis of mice immediately after exposure to the elevated plus-maze impairs their avoidance behavior on re-exposure to the apparatus
No full textABT-963 [2-(3,4-Difluoro-phenyl)-4-(3-hydroxy-3-methyl-butoxy)-5-(4-methanesulfonyl-phenyl)-2 H
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Ciproxifan, a histamine H3-receptor antagonist / inverse agonist, modulates methamphetamine-induced sensitization in mice
No full textBrain histamine and schizophrenia: Potential therapeutic applications of H3-receptor inverse agonists studied with BF2.649
No full textHistamine H1 receptor involvement in prepulse inhibition and memory function: Relevance for the antipsychotic actions of clozapine
No full textEnvironmental enrichment influences survival rate and enhances exploration and learning but produces variable responses to the radial maze in old rats
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