Effect of mastic gum, and vitamin e on ethanol/hcl-induced gastric ulcers in rats

Gastric ulcers were induced in the rat stomach by oral administration of ethanol/HCl [150 mM HC1 in 60% ethanol, 1 ml/ 100 g]. The protective effect of mastic gum, a resinous exudate of the tree of Pistacia lentiscus Linn Anacardiaceae, [500 mg/Kg], and vitamin E, a well known antioxidant, [100 mg/Kg] were investigated. Different gastric juice components [acidity, mucin and peptic activity] as well as gastric mucosal content of reduced glutathione, malondialdehyde, [as an index of lipid peroxidation] and prostaglandin E2 were estimated. Ethanol/HCl administration produced marked ulcers in the glandular part of rat stomach. Pretreatment with the protective agents significantly reduced the ulcer index and the protection afforded by mastic gum was greater than that of vitamin E. The protective effects of both mastic gum and vitamin E were accompanied by a significant decrease in mucosal content of malondialdehyde and a significant increase in mucosal content of reduced glutathione as compared to ethanol/HCl treated group. However, the anti-ulcer effect produced by mastic gum, only, was associated with a significant increase in mucosal content of prostaglandin E[2]. In 3-hour pylorus-ligated rats, mastic gum produced a significant decrease in free and total acidity while vitamin E caused no significant change in gastric acid secretion. The present data suggest that the anti-ulcer effect of mastic gum may be partly related to its antisecretory as well as antioxidant properties. On the other hand, the protective effect of vitamin E may be mainly related to its antioxidant effect

Binding studies of some antidiabetics to serum albumin by difference spectrophotometry

The binding of several antidiabetics to serum albumin was studied by difference spectrophotometry using a spectrophotometric probe 2-[4-hydroxy-benzeneazo] benzoic acid. The calculated constants for binding of the drugs to human serum albumin were 2.38x10[6], 1.78x10[6], and 1.87x10[4] for glyburide, tolbutamide and metformin respectively. While the values of binding to bovine serum albumin were 2.89x10[5], 2.04x10[5], and 2.14x10[4] for the same drugs. Drug-probe displacement studies showed that glyburide gave the greatest probe displacement followed by tolbutamide and metformin using both human and bovine serum albumins. This order of displacement of the anionic probe indicates that both hydrophobic character and ring substituents of the ligand contribute

effects of tricyclic and tetracyclic antidepressants on the levels of norepinephrine, dopamine and serotonin in rat brain

After 3 weeks of daily intraperitoneal administration of either incyclic [amitriptyline, clomipramine] or tetracyclic [maprotiline] antidepressants in a dose of 20 mg/kg each to male rats, the whole brain levels of norepinephrine and dopamine were significantly increased as compared to control values. In contrast, the level of serotonin increased only with the tetracyclic antidepressant maprotiline and this increase was moderate. However, it is not yet certain, how far these effects contribute to the mechanism of antidepressant action. A study of the turn-over rate and the activities of the enzymes along the monoamine metabolic pathway are currently underway for adequate interpretation of the results

effect of verapamil on brain monoamines of rats pretreated with nialamide and reserpine

The present work investigated the acute effect of verapamil on the brain levels of 5-hydroxytryptamine [5HT], dopamine [DA] and noradrenaline [NA] in nialamide and reserpine pretreated rats. Results showed that treatment of rats with verapamil [5 mug/kg] one hour prior to sacrifice significantly increased brain 5HT and decreased DA brain level. However, brain NA level showed no significant difference compared to control values. Treatment of rats with nialamide, significantly increased brain 5HT, DA and NA levels. In nialamide pretreated rats, verapamil [5 mug/kg] revealed a highly significant increase was slightly higher than that produced by either verapamil or nialamide alone, it did not reach statistical significance. Moreover, pretreatment of rats with nialamide completely blocked the verapamil-induced decrease in brain DA level. On the other hand, the treatment of rats with reserpine, significantly depleted brain 5HT, DA and NA levels. The verapamil-induced increase in brain 5HT was blocked by the pretreatment of rats with reserpine. However, reserpine pretreatment revealed a synergistic effect with the calcium antagonist on brain DA level, where a highly significant depletion was evident. The possible mechanisms by which verapamil induced these changes in brain monoamines was discussed

Verapamil: a calcium channel blocker and its effect on brain monoamines in the rat

The present work is an attempt to investigate the effect of verapamil, a calcium channel blocker, on brain 5 hydroxytryptamine [5 HT], dopamine [DA] and noradrenaline [NA]. Results showed that the intraperitoneal [i.p.] injection of verapamil in doses of 1, 5, 25 and 50 mug/kg, one hour prior to sacrifice, significantly increased brain 5 HT level. A significant decrease in brain DA was detected with doses of 5, 25 and 50 mug/kg of verapamil, while 1 mug/kg caused no significant change in this parameter. Brain NA level, however, was not significantly changed with all the doses of verapamil previously mentioned when measured one hour from the injection of the drug. The mechanism of action of verapamil in the management of affective disorders and the possibility of the involvement of brain 5 HT and DA was discussed