we have measured the competitive antagonistic effect of chlorpheniramine in bronchi of 8 normal and 12 asthmatic subjects. classical pharmacological theory states that the degree of competitive antagonism depends only upon 1) antagonist concentration at the receptor, and 2) receptor affinity. delivery and affinity also influence agonist responsiveness, but measurement of bronchial antagonism al...

Histamine Hi and H2 receptors are present in the canine renal circulation. We have examined the effects of H, and H2 receptor antagonists on autoregulation of renal blood flow in the dog. Renal arterial pressure was reduced in a step-wise fashion to 80 mm Hg by means of an adjustable aortic clamp positioned above the left renal artery. Infusion of H2 antagonists, cimetidine or ranitidine, into ...

The central histaminergic neuron system inhibits epileptic seizures, which is suggested to occur mainly through histamine 1 (H1) and histamine 3 (H3) receptors. However, the importance of histaminergic neurons in seizure-induced cell damage is poorly known. In this study, we used an organotypic coculture system and confocal microscopy to examine whether histaminergic neurons, which were verifie...

We examined the cerebral circulatory effects of intra-carotid infu­ sion of histamine or its receptor agonists in anesthetized rats. Cerebral blood flow was measured by two methods: an intracarotid I:l3Xe clearance technique and tissue sampling after systemic administration of the diffusible tracer, [14C]iodoantipyrine, Brain metabolic responses were estimated by the 2deoxyglucose method and ti...

BACKGROUND: Brain monoamines (such as histamine and dopamine) play an important role in emotions, cognition, reward and feeding behavior. The interactions between histamine and dopamine were studied in many physiological functions but this correlation is unclear in feeding behavior of chickens. The aim of this study was to investigate the interaction of central histaminergic and dopaminergic sy...

restraint-induced stress (rs) increases histamine concentration in the brain. there is no previous report regarding the role of histamine receptors in immunomodulatory effect of rs. in the present study the role of brain histamine receptors on reduction of humoral and cellular immune function induced by rs was evaluated. for this purpose male wistar rats (200-250 g) were immunized with sheep re...

Background. Itch can be transmitted by two parallel pathways, histaminergic and nonhistaminergic. Histaminergic itch is a subgroup of mechano-insensitive C-fibers, while nonhistaminergic polymodal C-fibers. Experimental models are used to study pruritus: histamine for the antagonizing H1-receptors, BAM8-22 cowhage activating Mas-related G protein-coupled receptors protease-activated receptors, ...

Restraint-induced stress (RS) increases histamine concentration in the brain. There is no previous report regarding the role of histamine receptors in immunomodulatory effect of RS. In the present study the role of brain histamine receptors on reduction of humoral and cellular immune function induced by RS was evaluated. For this purpose male Wistar rats (200-250 g) were immunized with sheep re...