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...

This article reviews the molecular biology of the interaction of histamine with its H1-receptor and describes the concept that H1-antihistamines are not receptor antagonists but are inverse agonists i.e. they produce the opposite effect on the receptor to histamine. It then discourages the use of first-generation H1-antihistamines in clinical practice today for two main reasons. First, they are...

BACKGROUND A human neuroblastoma cell line (Paju) was induced by retinoic acid (RA) to differentiate into neuron-like cells. MATERIALS AND METHODS We studied the expression and the possible role of histamine receptors H1 and H2 in retinoic-acid mediated differentiation by semiquantitative RT-PCR. We studied the effect of exogeneously added RA on the morphological change of the human neuroblas...

Histamine is the main mediator of urticaria and H1-receptor antagonists represent the treatment of choice in all patients with chronic urticaria. Leukotriene receptor antagonists as montelukast have also been used in patients with chronic urticaria unresponsive to H1-antihistamines alone. We report a patient with chronic urticaria whose disease was paradoxically exacerbated by H1-antihistamines...

We investigated the specific H1 receptor antagonist, clemastine, in 15 children with asthma. In the respiratory unit, clemastine was an effective bronchodilator but in a clinical trial we could not show any significant benefit compared with placebo.

Since exogenous histamine has been previously shown to increase the somatostatin (SS) receptor-effector system in the rat frontoparietal cortex and both histamine H1-receptor agonists and SS modulate higher nervous activity and have anticonvulsive properties, it was of interest to determine the participation of the H1-histaminergic system in this response. The intracerebroventricular (i.c.v.) a...