R Nwankwoala, O Georgewill, U Georgewill
a suum extract, gastric acid secretion, inhibition, peptic ulceration
R Nwankwoala, O Georgewill, U Georgewill. Inhibitory effects of ascaris suum extract On gastric acid secretion in rats. The Internet Journal of Pharmacology. 2008 Volume 7 Number 1.
The effects of Ascar’s Suum (A. Suum) extract on gastric acid secretion were investigated in urethane-anaesthetised rats. Three determinations were done viz (1) the acid content when no drug was administered (2) the acid content when histamine was injected and (3) the acid content when the A. Suum extract was given alone or after histamine was administered. The extract (5.5 or 14mg/kg) reduced histamine-induced gastric acid secretion to the control value. At 14mg/kg the extract also reduced basal gastric acid secretion. At the peak of histamine-induced gastric acid secretion, the administration of the extract promptly reduced the gastric acid secretion to basal values. These results indicate that extracts of Ascaris Suum inhibit gastric acid secretion.
Ascaris Summ is a common parasitic worm found in the small intestine of pigs. Its equivalent in man is
Materials and method
Animals: Randomly selected young (5-10 weeks old) Albino rats of both sexes weighing 150g-
Drugs and Reagents
Histamine (acid phosphate), phenolphthalcin indictor, urethane and trichloroacetic acid were obtained from Sigma Chemicals U.K.
The protein precipitate was redissolved in the saline. This mixture was dialyzed for 24 hours in distilled water in order to remove sodium chloride and trichloroacetic acid. The dialyzed material was then freeze-dried. The resulting freeze-dried substance was stored for use and this was the
Measurement of Gastric Acid Secretion
Each animal was anaesthesized with 25% Urethane (0.6 m1/10g body weight). Subsequently, a tracheostomy was performed and a canula inserted into the trachea and ligated to ensure adequate respiration. Another canula was inserted into the oesophagus through the mouth and ligated. This canula is continuous with a drip set tube which runs from the reservoir bottle containing saline which is placed in the water-bath set at 37 0 C. Thereafter duodenostomy was performed near the gastroduodenal junction and another canula inserted into the stomach through the pyloric end and ligated. The stomach was washed of the food particles. The effluent was collected through the canula inserted into the stomach at the rate of about 9 to 15 mls every 20 minutes. Nothing the volume of effluent, each collection was volumetrically titrated against 0.0025M sodium hydroxide. Two or 3 drops of phenolphthalein was used as the indicator. The volume of the base used to neutralize the acid was recorded, from which the amount of acid in a given effluent was quantitated. Basal secretion effluents were usually collected before the injection of the drugs.
Four (4) types of experiments were carried out: (1) Basal Secretion and Histamine-stimulated gastric acid secretion, (2) Histamine-stimulated gastric acid secretion in the presence and absence of the extract, the effect of the extract on basal secretion, (3) the interception of Histamine-stimulated gastric acid secretion at Peak by the administration of the two doses of the extract used and (4) the effect of the co-administration of the extract and histamine on gastric acid secretion. For each experiment, basal secretion effluents were collected and this was repeated in five animals. In the other experiments, 20mg/kg, histamine was administered intramuscularly
As shown in Fig 1, histamine at the dose of 30mg/kg produced 70% gastric acid secretion above the basal values. This histamine-induced acid secretion peaked at 2½ hours and remained high at 4½ when the experiment was terminated. Co-administration of 20m1/kg histamine and 14mg/kg
As illustrated in Fig. 3, when the Ascaris suum extract was administered at the peak of Histamine-induced gastric acid secretion 21/3 hours following series of histamine administration, the two doses of the extract used (5mg/kg an 14mg/kg) reduced the gastric acid secretion to the basal values. This result was also obtained when the extract was co-administered with histamine right from the onset of the experiment as shown in Fig. 4 For example, there was no significant difference (p>0.05) in gastric secretion between the basal value and that obtained when Histamine was co-administered with the ascaris extract whereas histamine administered alone significantly (p<0.001) increased gastric acid secretion.
It has been demonstrated that the extracts of
In this study, the two doses used viz 5.5mg/kg and 14mg/kg
These data suggest that the extract may produce its inhibitory effect on gastric acid secretion by altering the histamine and cholinergic receptor configurations on the partietal cells and not by H2 receptor blockade.
This view is supported by earlier finding in our laboratory that the Ascaris extract also inhibited carbachol-induced gastric acid secretion (Ezeamuzie and Nwankwoala – unpublished data). It is also possible that at much lower concentrations of the extract e.g microgram or less, dose dependent inhibitory response may be observed. This possibility is currently undergoing investigation in our laboratory.