PubMed HealthSearch

Biomedical subjects

A K Ganguly

Publications and source records attributed to A K Ganguly.

At least 19 recordsLinked to original sources

Discovery and preliminary pharmacology of Sch 37370, a dual antagonist of PAF and histamine.

From a series of amide analogs of the histamine H1 antagonist, azatadine, a potent, orally active, dual platelet-activating factor (PAF) and histamine antagonist, Sch 37370, namely 1-acetyl-4-(8-chloro-5,6-dihydro-11H-benzo- [5,6]cyclohepta[1,2-b]pyridin-11-ylidine)piperidine, was discovered. Sch 37370 selectively inhibits PAF-induced aggregation of human platelets in vitro (IC50 = 0.6 microM), and in vivo inhibits PAF- and histamine-induced bronchospasm in guinea pigs with ED50 values of 6.0 and 2.4 mg/kg p.o., respectively. Sch 37370 is expected to be more efficacious than single mediator antagonists in allergic diseases, such as asthma.

Histamine Antagonists

Gastric mucosal protection during restraint stress: histologically identifiable gastric mucosal glycosaminoglycan content in albino rats.

Male albino rats were subjected to restraint stress for 20 h following 24 h fasting. Tissues from oxyntic and pyloric gland areas of the stomach were processed and stained by the PAS technique to assess the glycosaminoglycan content of the gastric mucosa. The result was compared with that of control rats. A significant reduction in PAS positive materials in both oxyntic and pyloric gland areas of gastric mucosa was observed following 20 h restraint stress. The study indicates the significant role of gastric mucosal glycosaminoglycans in the protection of gastric mucosa against ulcers that develop under restraint stress.

Animals

Effect of pylorus ligation on gastric mucosal mast cell population in normal and adrenalectomised albino rats.

Pylorus ligation in normal albino rats acts like a stressor leading to degranulation of mast cells in gastric mucosa, thereby decreasing their number. This decrease is less pronounced when pylorus ligation is done in adrenalectomized rats. This implies that action of a stressor on gastric function involves the adrenal steroids which liberate the powerful gastric stimulant histamine from gastric mucosal mast cells.

Adrenal Cortex

Vagus nerves and the gastric tissue histamine concentration in pylorus ligated albino rats.

Gastric tissue histamine concentration was determined, 6 and 16 hours after pylorus ligation in vagus intact and vagotomized albino rats and the results were compared with those of respective control animals, sacrificed, 6 and 16 hours after ether anaesthesia alone. The gastric tissue histamine concentration of rats subjected to none of the experimental situations was also determined and taken into comparison. The results show that the stress of pylorus ligation reduced the gastric tissue histamine concentration, the reduction being more with increased duration of stress. On the other hand, subdiaphragmatic vagtomy preserved the histamine concentration of gastric tissue irrespective of the duration to which the animals were exposed following pylorus ligation. It appears that increase in vagal discharges during stress leads to increased liberation of histamine from the gastric wall, thereby, reducing the gastric tissue histamine concentration; the reduction being proportional to the duration of stress and increase in vagal discharges, whereas, in the absence of vagal impulses following subdiaphragmatic vagotomy, the gastric tissue histamine concentration is preserved in spite of the stress to which the animals were exposed.

Animals

Effect of sub-diaphragmatic vagotomy on gastric mucosal mast cell population in pylorus ligated rats.

Gastric mucosal mast cell population was studied following sub-diaphragmatic vagotomy in albino rats, 6 and 12 h after pylorus ligation. Sub-diaphragmatic vagotomy significantly increased the gastric mucosal mast cell population in both 6 and 12 h groups, the increase being more in the latter. The results suggest that the vagal impulses act on the gastric mucosal mast cells causing their degranulation. Following vagotomy the contents stay bound within the mast cells. Increase in mast cell population with the longer experimental situation was possibly due to the continuation of normal turnover of the mast cells in the gastric mucosa. The present study, however, does not lead to a conclusion that the vagal influence on mast cell population is similar throughout the gastro-intestinal tract.

Animals

Effect of bilateral adrenalectomy and parenteral betamethasone on gastric mucosal mast cell population in albino rats.

The histamine-laden mast cells of gastric mucosa in albino rats are shown to degranulate on administration of Betamethasone, but they increase in number in adrenalectomized rats. It is concluded that Betamethasone, and also adrenal glucocorticoids increase gastric secretion by liberating histamine from mast cells and histamine in turn acts on the gastric glands.

Adrenalectomy

Effect of subdiaphragmatic vagotomy on production of gastric ulcers in pylorus-ligated albino rats.

A reduction in volume and free and total acidity of gastric content was noted along with reduction in ulcer index, with a shift of the site of ulceration from fundus to the glandular part of the stomach, following vagotomy in pylorus-ligated rats. Low volume and acidity explains the absence of ulcers in the fundus, but the increased involvement of glandular part in ulceration is possibly due to weakening of the mucosal barrier following vagotomy.

Animals