Histamine H1 receptors have been demonstrated on adherent rheumatoid synovial cells using biochemical and radioligand binding assays in vitro. The addition of histamine (17.8 mumol/l) to nine primary cultures of adherent rheumatoid synovial cells resulted in a two- to 21-fold increase in the production of prostaglandin E (PGE). This increase was inhibited by three H1 receptor antagonists (mepyr...

1 Histamine produced dose-dependent contractile responses on both isolated perfused ear arteries and aortic strips of the rabbit. These responses were blocked by mepyramine and potentiated by both metiamide and dithiothreitol. 2 In the presence of maximum potentiation by metiamide, dithiothreitol still potentiated the contractile response to histamine of both preparations. 3 In the presence of ...

The effects of Mono sodium glutamate on smooth muscles were studied using the guinea-pig isolated ileum. Mono sodium glutamate produced spasmogenic effect. Atropine blocked the contractile response elicited by Mono sodium glutamate whereas mepyramine and hexamethonium failed to do so. These findings suggest a cholinergic involvement at post ganglionic site of action.

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...

The histaminergic system modulates numerous physiological functions such as wakefulness, circadian rhythm, feeding, and thermoregulation. However, it is not yet known if this system is also involved in psychological stress-induced hyperthermia (PSH) and, if so, which histamine (H) receptor subtype mediates the effect. Therefore, we investigated the effects of pretreatments with intraperitoneal ...

Undifferentiated monolayers of the hamster vas deferens smooth-muscle cell line, DDT1MF-2, were grown on glass coverslips and loaded with the Ca(2+)-sensitive fluorescent dye fura-2. Stimulation with histamine produced a rapid and maintained increase in intracellular free Ca2+ ([Ca2+]i), with an EC50 of 7.0 +/- 0.7 microM. The initial rise in [Ca2+]i can be attributed to Ca2+ release from intra...

Rats exposed to lead (lead acetate) in doses of 0.2 and 0.5 mg/ml in drinking water for a period of 90 days showed mild to moderate changes in food consumption compared to control group. Drug interactions in lead exposed rats with metoclopramide, atropine sulphate, propranolol, cyproheptadine and mepyramine maleate when administered intraperitoneally caused -30 to +30 percentage variation in fo...

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...

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...