Blood-tumor barrier (BTB) reduce the permeability for drugs into tumor tissues. We found that histamine might serve as an essential regulator of BTB function. Further, we aim to determine the role of H2 receptor expression in BTB permeability, and elucidate the underlying mechanisms thereof. Transmission electron microscopy showed that histamine disrupted the integrity of tight junctions (TJ) a...

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...

We utilized the technique of polymerase chain reaction with oligonucleotide primers based upon the nucleotide sequence of the canine H2 histamine receptor gene which we recently isolated to clone its human homologue. Transfection of a construct of this gene in Colo-320 DM cells led to the expression of a receptor that bound to [methyl-3H] tiotidine and was linked to 3',5'cyclic adenosine monoph...

BACKGROUND H2-histamine receptors mediate a wide range of physiological functions extending from stimulation of gastric acid secretion to induction of human promyelocyte differentiation. We have previously cloned the H2-histamine receptor gene and noted that only three amino acids on the receptor were sufficient to define its specificity and selectivity. Despite only modest overall amino acid h...

In the present study, the effects of intracerebroventricular (ICV) injections of histamine, chlorpheniramine (H1-receptor antagonist) and ranitidine (H2-receptor antagonist) were investigated on visceral nociception induced by an intraperitoneal (IP) injection of acetic acid in rats. The latency time to the beginning of the first abdominal wall contraction (the first writhe) was recorded and th...

The role of histamine in the regulation of food and water intake in mammals and birds of the review, this study evaluated the effects of intraperitoneal administration of famotidine as histamine H2 -receptor antagonist, in broiler chicks on feed intake and satiety in water and was hungry. 32 male Ross broiler chicks reared in groups of four weeks, 16 samples (control and test ) were then inject...

Serotonin and histamine H1, H2 receptor agonists or antagonists inhibited [3H]histamine uptake by HL-60 cells, according to the following order of potency: impromidine greater than 4-MH greater than histamine greater than AET greater than PEA and: cimetidine, histamine greater than diphenhydramine, serotonin. It is concluded that histamine uptake by HL-60 cells was specifically controlled by th...

Histamine is a well-known mediator eliciting a broad range of responses in different cell types. Four different subtypes of G protein-coupled histamine receptors (H1-H4) have been cloned and pharmacologically characterized. However, involvement of the different histamine receptor subtypes in immunomodulatory functions of bronchial epithelium has only been investigated marginally. The expression...

objective(s): the present study investigated the effects of microinjection of histamine and histamine h1, h2, and h3 receptor antagonists, chlorpheniramine, ranitidine and thioperamide, respectively into the primary somatosensory cortex (psc) on inflammatory pain.   material and methods: two stainless steel guide canulas were bilaterally implanted into the psc of anaesthetized rats. inflammator...