Quantitative and histological evaluations for the potentiality of pilocarpine on tramadol induced xerostomia and structural alterations in Rats parotid gland

Tramadol is a centrally acting analgesic with weak opioid agonist properties, which also has monoaminergic activity, exerted via inhibition of neuronal uptake of serotonin and norepinephrine. Tramadol is generally well tolerated and the most common adverse events are nausea, dizziness, drowsiness, sweating, vomiting and dry mouth. The effect of intraperitoneal injection of tramadol and pilocarpine were studied in rats on the flow of saliva, histological and histochemical change in the parotid salivary gland. The rats were divided into three groups, first group, rats received saline and used as control. The second group treated with 10 mg tramadol hydrochloride for three days. The third group treated with tramadol hydrochloride for three days followed with 1 mg pilocarpine. The rats were sacrificed at the fourth day after the end of experimental procedure. The administration of tramadol caused decreased in salivary flow rate by approximately 60 %. The parotid histopathological changes include vacuolation and atrophy of acini and excessive widening of the interstitial tissue area which are replaced by extensive fibrosis fibrosis mostly associated with the degenerated ducts and acini and their replaced by inflammatory cells.