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 role of the basolateral amygdala (BLA) in the consolidation of aversive memory is well established. Here we investigate the involvement of the histaminergic system in BLA on this variable. Rats were chronically implanted with bilateral cannulae in the BLA and after recovery were trained in a one-trial step-down inhibitory avoidance task. Immediately after training histaminergic compounds ei...

Cytidine 5'-diphosphocholine (CDP-choline) is an endogenously synthesized mononucleotide which exerts a variety of physiological effects by altering central cholinergic transmission. Administered intracerebroventricularly (i.c.v.) or intravenously, it reverses haemorrhagic hypotension in rats, apparently by the activation of central cholinergic receptors. The study was undertaken to investigate...

Orexins (also known as hypocretins) play critical roles in the regulation of sleep/wakefulness states by activating two G-protein coupled receptors (GPCRs), orexin 1 (OX1R) and orexin 2 receptors (OX2R). In order to understand the differential contribution of both receptors in regulating sleep/wakefulness states we compared the pharmacological effects of a newly developed OX2R antagonist (2-SOR...

Heart of England NHS Foundation Trust, Birmingham, UK School of Life and Health Sciences, Aston Brain Centre, Aston University, Birmingham, UK Children’s Epilepsy Surgery Programme, The Birmingham Children’s Hospital NHS Foundation Trust, Birmingham, UK Department of Neuropsychiatry, Birmingham and Solihull Mental Health NHS Foundation Trust, Birmingham, UK Sobell Department of Motor Neuroscien...

Histamine is an important chemical messenger that regulates multiple physiological processes in both vertebrate and invertebrate animals. Even so, how glial cells and neurons recycle histamine remains to be elucidated. Drosophila photoreceptor neurons use histamine as a neurotransmitter, and the released histamine is recycled through neighboring glia, where it is conjugated to β-alanine to form...

Although the effectiveness of histamine-related drugs in the treatment of peripheral and central vestibular disorders may be explained by their action on the vestibular nuclei, it has also been shown that antivertigo effects can take place at the peripheral level. In this work, we examined the actions of H3 histaminergic agonists and antagonists on the afferent neuron electrical discharge in th...

Background. Itch can be transmitted by two parallel pathways, histaminergic and nonhistaminergic. Histaminergic itch is a subgroup of mechano-insensitive C-fibers, while nonhistaminergic polymodal C-fibers. Experimental models are used to study pruritus: histamine for the antagonizing H1-receptors, BAM8-22 cowhage activating Mas-related G protein-coupled receptors protease-activated receptors, ...