Whether a state of nasal hyperresponsiveness influences antigen-induced biphasic nasal blockage and sneezing were examined using a guinea pig model of allergic rhinitis. Sensitized animals were challenged with an antigen, Japanese cedar pollen, once every week. Before the 13th challenge, the animals were randomly divided into 2 groups, and then the 13th challenge was performed (Groups A-0 and B...

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...

In the present study, the effects of morphine and pethidine on coronary vessel resistance (CPP), blood pressure (BP), and experimental myocardial infarction-induced cardiac arrhythmia were investigated. Both morphine and pethidine induced a fall in CPP and BP and inhibited the cardiac arrhythmia. The morphine effects on CPP and BP were largely blocked by mepyramine. The effects of pethidine, on...

Neem leaf alcoholic extract (NLE) was investigated for its effects on the ECG and blood pressure of rat. Intravenous administration of NLE (100, 300 and 1000 mg/kg) resulted in initial bradycardia followed by cardiac arrhythmia in rats. NLE produced a significant and dose-related fall in blood pressure which was immediate, sharp and persistent. Pre-treatment with either atropine or mepyramine f...

Topically applied aspirin has recently been reported to decrease histamine-induced itch in human volunteers. Our aim is to confirm this and to study the antipruritic ability of topical aspirin in inflamed skin. In 24 non-atopic volunteers, an inflammatory skin reaction was induced in forearm skin at 5 different sites by sodium lauryl sulphate contained in Finn Chambers. Aspirin 10%, aspirin 1%,...

Amrinone is a new synthetic drug that increases contractile strength of mammalian heart muscle; however, its mechanism of positive inotropic action has not been determined. We now report that amrinone (0.053-5.3 mM) consistently restores typical slow response electromechanical activity fo K+-depolarized atrial and ventricular myocardial preparations from guniea pigs. This action was blocked in ...

The effects of H1-receptor blocking agents, pyrilamine, promethazine, and diphenhydramine, on the amplitude and time course of endplate potentials (e.p.ps) were studied in the sartorius muscles of frogs. H1-receptor blockers (10(-5)-10(-4) M) reduced the amplitude of e.p.ps recorded intracellularly without affecting the resting membrane potential. The acetylcholine potential was decreased by pe...