Histamine released from ECL cells elicits responses from a variety of cellular targets in the vicinity. Three sets of receptors are involved (H1, H2 and H3). Receptor occupation is promptly transduced into cellular responses. The responses, in turn, are terminated by diverse mechanisms: enzymatic inactivation, cellular uptake and desensitization at the receptor level. Under specific pathologica...

BACKGROUND Histamine can induce coronary vasospasm, leading to variant angina and acute myocardial infarction. However, the role of histamine in thrombus formation is ill defined. Hence, this study investigates whether histamine induces tissue factor (TF) expression in vascular cells. METHODS AND RESULTS Histamine (10(-8) to 10(-5) mol/L) induced TF expression in a concentration-dependent man...

Mast cells promote both innate and acquired immune responses, but little is known about the effect of mast cells on T regulatory (T(reg)) cell function. In this study, we show for the first time that the capacity of murine CD4(+)CD25(+) T(reg) cells to suppress in vitro proliferation by CD4(+)CD25(-) T responder (T(resp)) cells in response to anti-CD3/anti-CD28 mAb-coated beads was reduced in t...

BACKGROUND Repeated administration of certain drugs could result in an enhancement of the behavioral effects of those drugs. In the present study, the effect of repeated administration of histamine on amnesia induced by post-training administration of the drug was examined. METHODS A single trial step-down inhibitory (passive) avoidance task was used for memory assessment in male NMRI mice. ...

Histamine is an accepted neurotransmitter and/or neuromodulator in the central nervous system (CNS). Its neuronal system in the brain is well organized, with cell bodies localized in a small area of the posterior hypothalamus. Diverse biological actions of histamine are mediated via three classes of receptors termed H1, H2, and H3. The existence of other histamine receptor subtypes is likely in...

The diverse physiological functions of histamine are mediated through distinct histamine receptors. Mast cells are major producers of histamine, yet effects of histamine on mast cells are currently unclear. The present study shows that histamine induces chemotaxis of mouse mast cells, without affecting mast cell degranulation. Mast cell chemotaxis toward histamine could be blocked by the dual H...

Wang, L. D., M. Wang, A. Todisco, E. Grand, and J. Del Valle. The human histamine H2 receptor regulates c-jun and c-fos in a differential manner. Am J Physiol Cell Physiol 278: C1246–C1255, 2000.—Previously, we demonstrated that activation of the human H2 receptor (hH2R) leads to an increase in c-fos transcription and cell proliferation. The purpose of these studies was to examine whether hH2R ...

Levodopa is the most effective therapy for the motor deficits of Parkinson's disease (PD), but long term treatment leads to the development of L-DOPA-induced dyskinesia (LID). Our previous studies indicate enhanced excitability of striatal cholinergic interneurons (ChIs) in mice expressing LID and reduction of LID when ChIs are selectively ablated. Recent gene expression analysis indicates that...