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...

In this study, the effects of intraperitoneal (ip) injection of physostigmine, subcutaneous (sc) injection of atropine, and intracerebroventricular (icv) injections of histamine, chlorpheniramine (H(1)-receptor antagonist), and ranitidine (H(2)-receptor antagonist) in separate and combined treatments were investigated during yawning in rats. Physostigmine at a dose of 0.25 mg/kg produced the hi...

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...

Dopamine has an effective role on gastric acid secretion (GAS). The role of peripheral and central dopamine D1/DA1 receptors on stimulated GAS are unknown. The objective of the present study was to use SKF38393 and SCH23390 on stimulated GAS. For all gastric sampling, animals (Sprague Dawley rats) were anesthetized and a polyethylene tube was introduced into the stomach through esophagus and a ...

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 ...

T he existence of histamine receptors and histamine in the heart has been known since at least the 1940s (1) and cloning of human histamine receptors began around the 1990s (2). Nevertheless, developments relating to histamine have not been highlighted. Also, its role in cardiovascular physiology, such as in the renin–angiotensin or the sympathetic nervous system where it is central to understa...

Two azide analogues of ketanserin (6- and 7-azido-3-[2- [4-(4-fluorobenzoyl)-1-piperidinyl]ethyl]-2, 4(1H,3H)-quinazolinedione) were synthesized and tested as possible photoaffinity probes for serotonin-S2 and histamine-H1 receptors. In reversible binding experiments, the azides showed high affinity for both receptor types. When membrane preparations were incubated with nanomolar concentrations...

It is increasingly clear that histamine mediates a variety of lymphocyte functions. Further understanding of these mechanisms requires a method for the analysis of histamine membrane receptors on the lymphocyte surface. We report now a biochemical technique for the identification and quantitation of specific histamine H1 and H2 receptors of lymphocytes. The method can be performed on small numb...