Effects of benzodiazepine and pilocarpine on rat parotid glands: histomorphometric and sialometric study

Benzodiazepines are among the most frequently prescribed drugs and are often related with dry mouth. Pilocarpine is a cholinergic agonist that increases salivary flow rate and has been used to treat xerostomia. This study aimed to measure salivary flow rate of rats under chronic treatment with benzodiazepine (Diazepam), to analyze by histomorphometry the effects of the drug in the parotids glands and to verify the effect of the pilocarpine in glandular parenchyma and in the salivary flow rate. Seventy-two male Wistar rats were allocated to four groups. Control groups received saline during 60 days (C60) and pilocarpine (Pilo) during 60 days. Experimental groups were dealt with Diazepam associated with saline (DS), and Diazepam associated with pilocarpine (DP) during 60 days. The stimulated salivary flow rate was obtained by using the gravimetric method. After the animals were killed, parotid glands were removed and mass and size were determined. The specimens were processed and stereological analysis revealed cell volume. Mean values of size and salivary flow rate varied from 9.007 mm and 0.015 mg/min in DS to 7.854 mm and 0.029 mg/min in DP, respectively. ANOVA showed statistically significant differences between groups for size (p=0.0028) and salivary flow rate (p=0.0003). Psychotropic drugs caused hyposalivation in rats and acinar hypertrophy in their parotid glands. Pilocarpine, a cholinergic agonist with topical appliance, showed significant secretagogue action in the treatment of hyposalivation induced by Diazepam chronic use.