Effect of ouabain on submandibular salivary gland and level of zinc and copper in saliva and serum in rat

In this study, the effect of various doses of ouabain (1, 2, and 5 mg/kg, i.p.) on weight and flow rate of submandibular gland (SMG) and changes in zinc and copper levels in pure saliva and serum of rats was investigated. The time interval between injection of drug and sampling was 30 min. In addition, the effect of a single and toxic dose of ouabain (5 mg/kg, i.p.) in various time intervals (30 min, 1, 2, 3, 7, and 14 days) was also studied. The results showed that in all groups, normalized weight of SMG did not differ significantly. Meanwhile, flow rate decreased 30 min after injection in those animals receiving 2 and 5 mg/kg ouabain and one day after injection in the group receiving 5 mg/kg ouabain. After this time period, all flow rates recovered. In addition, level of zinc increased in serum and saliva in those groups receiving 2 and 5 mg/kg ouabain after 30 min, but it decreased in the group receiving 1 mg/kg of the drug and in recovered groups after 2, 3, and 7 days, serum zinc concentration showed a negligible elevation. Further analysis of data showed that there was no correlation between serum and salivary copper levels. In this respect, only salivary copper level decreased in groups receiving 1, 2, and 5 mg/kg of ouabain and in recovered group after 1 day, whereas copper level only decreased in serum in groups receiving ouabain after 2, 3, and 7 days. Therefore, alterations in zinc level correlate with the inhibitory effects of ouabain on sodium-potassium pump, which may also be the mechanism responsible for the uptake or transport of zinc in this gland. It is noteworthy that alterations in zinc and copper level were opposite of each other in saliva of groups receiving 2 and 5 mg/kg of ouabain and in recovery groups and also in the serum obtained from recovery groups. Taken together, it seems that a period of 14 days is enough for recovery from all of the changes due to the toxic doses of ouabain.