Presynaptic receptors for dopamine, histamine and serotonin that are located on dopaminergic, histaminergic and sertonergic axon terminals, respectively, function as autoreceptors. Presynaptic receptors also occur as heteroreceptors on other axon terminals. Auto- and heteroreceptors mainly affect Ca(2+) -dependent exocytosis from the receptor-bearing nerve ending. Some additionally subserve oth...

The effect of histamine on bovine isolated retinal small arteries (internal diameter, approximately 240 microns) was studied. Histamine induced a concentration-dependent relaxation in 43 of 53 vessels. The histamine-induced relaxation involves primarily activation of H1-receptors, with H2-receptors also affected as evidenced by the effect of selective histamine-receptor agonists and antagonists...

Extracellular ATP exerts a variety of biological actions through several kinds of P2 receptor in HL-60 promyelocytes. We show that stimulation of P2Y2 receptors with ATP and analogs resulted in the inhibition of a subsequently histamine-induced cAMP production and functional differentiation. Treatment of the cells with phorbol 12-myristate 13-acetate also blocked the histamine-mediated cAMP gen...

The histamine H4 receptor (H4R) was first noted as a sequence in genomic databases that had features of a class A G-protein coupled receptor. This putative receptor was found to bind histamine consistent with its homology to other histamine receptors and thus became the fourth member of the histamine receptor family. Due to the previous success of drugs that target the H1 and H2 receptors, an e...

The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (α-methylhistamine) or antagonist (carcini...

In the present study, the effects of an intracerebroventricular (i.c.v.) dose of histamine (0.1, 1.0 or 10.0 micrograms) on the hippocampal somatostatin (SS) receptor/effector system in Wistar rats were investigated. In view of the rapid onset of histamine action, the effects of histamine on the somatostatinergic system were studied 2 h after its administration. Hippocampal SS-like immunoreacti...

BACKGROUND Atopic dermatitis constitutes a most burdensome chronic inflammatory skin disease. Standard treatment is cumbersome and often targets its main symptom, pruritus, only insufficiently. FINDINGS Recent advances in our understanding of the role of histamine and its four receptors suggest new approaches which target the histamine receptors alone or as combination therapies to more effic...

Histamine membrane receptors are defined as either H1 (blocked by diphenhydramine-like antagonists) or H2 (blocked by cimetidine-like agents). We now report the solubilization, separation, and partial characterization of specific H1 and H2 membrane receptors from calf thymocytes. Membrane fragments were incubated with [3H]histamine either alone or with unlabeled histamine, diphenhydramine, or c...

Histamine and prostaglandins (PGs) play a variety of physiological roles as autacoids, which function in the vicinity of their sources and maintain local homeostasis in the body. They stimulate target cells by acting on their specific receptors, which are coupled to trimeric G proteins. For the precise understanding of the physiological roles of histamine and PGs, it is necessary to clarify the...

Champion, Hunter C., Trinity J. Bivalacqua, David G. Lambert, Rasheed A. Abassi, and Philip J. Kadowitz. Analysis of vasoconstrictor responses to histamine in the hindlimb vascular bed of the rabbit. Am. J. Physiol. 277 (Regulatory Integrative Comp. Physiol. 46): R1179–R1187, 1999.—Hemodynamic responses to histamine were investigated in the anesthetized rabbit. Intravenous injections of histami...