BACKGROUND AND PURPOSE Histamine and prostaglandin E2 (PGE2 ), directly and via their effects on other cells, regulate the behaviour of vascular smooth muscle (VSM), but their effects on human VSM are incompletely resolved. EXPERIMENTAL APPROACH The effects of PGE2 on histamine-evoked changes in intracellular free Ca(2+) concentration ([Ca(2+) ]i ) and adenylyl cyclase activity were measured ...

The substantia nigra pars reticulata (SNr) is a key basal ganglia output nucleus. Inhibitory outputs from SNr are encoded in spike frequency and pattern of the inhibitory SNr projection neurons. SNr output intensity and pattern are often abnormal in movement disorders of basal ganglia origin. In Parkinson's disease, histamine innervation and histamine H3 receptor expression in SNr may be increa...

BACKGROUND Histamine is a biogenic amine that has been shown to contribute to several pathological conditions, such as allergic conditions, experimental encephalomyelitis, and malaria. In humans, as well as in murine models of malaria, increased plasma levels of histamine are associated with severity of infection. We reported recently that histamine plays a critical role in the pathogenesis of ...

Histamine is a neurotransmitter involved in a number of physiological and neuronal functions. In mammals, such as humans, and rodents, the histaminergic neurons found in the tuberomamillary nucleus project widely throughout the central nervous system. Histamine acts as positive modulator of GABAA receptors (GABAARs) and, in high concentrations (10 mM), as negative modulator of the strychnine-se...

Histamine is highly concentrated in the heart of animals and humans. Excessive release in pathophysiological conditions, such as immediate hypersensitivity and septic shock, causes cardiac dysfunction and arrhythmias. Previous pharmacological studies revealed that H(1) and H(2) receptors mediate these effects. Yet, an accurate estimate of the distribution and molecular characteristics of cardia...

Several lines of evidence have indicated that many nuclei in the brain including preoptic nucleus, AV3V, subfornical organ, septal area and lateral hypothalamus are the targets of efferents from chemo-sensitive and pressure-sensitive systems. These areas may concern with regulation of fluid homeostasis. In the present study, intracerebroventricular injections were carried out in all experiments...

Histamine is not only a crucial cytokine in the periphery but also an important neurotransmitter and neuromodulator in the brain. It is known to act on metabotropic H1-H4 receptors, but the existence of directly histamine-gated chloride channels in mammals has been suspected for many years. However, the molecular basis of such mammalian channels remained elusive, whereas in invertebrates, genes...

The preoptic area/anterior hypothalamus, a region that contains neurons that control thermoregulation, is the main locus at which histamine affects body temperature. Here we report that histamine reduced the spontaneous firing rate of GABAergic preoptic neurons by activating H3 subtype histamine receptors. This effect involved a decrease in the level of phosphorylation of the extracellular sign...

In human aortic smooth muscle cells, prostaglandin E2 (PGE2) stimulates adenylyl cyclase (AC) and attenuates the increase in intracellular free Ca2+ concentration evoked by activation of histamine H1 receptors. The mechanisms are not resolved. We show that cAMP mediates inhibition of histamine-evoked Ca2+ signals by PGE2 Exchange proteins activated by cAMP were not required, but the effects wer...

Drugs with antihistamine action are the most commonly prescribed medication in daily dermatologic practice, both to adults and children. This article addresses new concepts of the role of histamine receptors (H1 receptors) and discusses the anti-inflammatory effects of these drugs. Second generation antihistamines differs from first generation because of their high specificity and affinity for ...