The role of histamine H1 and H2 receptors in the lung is not clear. H1 receptor blockade results in bronchodilatation and inhibition of histamine induced bronchoconstriction. H2 receptor blockade in vitro prevents the normal negative feedback of histamine on further mediator release in antigen challenge. Bronchospasm in guinea pigs given antigen challenge is enhanced by previous administration ...

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...

We investigated the effects of a neurokinin-1 (NK(1)) receptor antagonist (SR-140333) and a NK(2) receptor antagonist (SR-48968) on airway responsiveness and on the function of neuronal M(2) muscarinic receptors, which normally inhibit vagal acetylcholine release, in guinea pigs infected with parainfluenza virus. Antagonists were given 1 h before infection and daily thereafter. Four days later,...

The aim of the present study was to investigate whether and by which mechanism; histamine can induce state-dependent retrieval of passive avoidance task. The pre-training or pre-test intracerebroventricular (i.c.v.) injection of histamine (20µg/mouse) impaired retrieval, when it was tested 24 h later. In the animals, which retrieval was impaired due to histamine pre-training administration, pre...

The effects of both an H1 receptor antagonist and an H2 receptor antagonist on changes in monovalent ion flux induced by topical sodium taurocholate were studied in antrectomised dogs fashioned with a denervated fundic pouch. The magnitude of taurocholateinduced ion flux was unaffected by topical administration of H1 or H2 receptor antagonists. Parenteral administration of H1 or H2 receptor ant...

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 ...

conclusions anesthesiologists need to be aware of dextromethorphan’s clinical pharmacology because recreational abuse of the drug has become increasingly common in adolescents and young adults. case presentation a 30-year-old man with a history of a nasal fracture was scheduled to undergo an elective septorhinoplasty. he reported daily consumption of large quantities (1440 to 1800 mg) of dextro...

The local intra-arterial infusion of histamine, in doses which produce maximal increases in protein efflux, failed to increase lymph total protein concentration in canine forelimbs perfused at constant inflow with autologous blood from dogs subjected to severe hemorrhagic hypotension. Norepinephrine and isoproterenol in low concentrations were less effective in antagonizing protein efflux produ...

The present study was designed to investigate the effect of once daily for 7-day (subchronic treatment) dosing of histamine H3 receptor antagonists, ciproxifan (CPX) (3 mg/kg, i.p.), and clobenpropit (CBP) (15 mg/kg, i.p), including clozapine (CLZ) (3.0 mg/kg, i.p.) and chlorpromazine (CPZ) (3.0 mg/kg, i.p.), the atypical and typical antipsychotic, respectively, on MK-801(0.2 mg/kg, i.p.)-induc...