Functional and structural adaptation of the parotid gland to medium-term chronic ethanol exposure in the rat

Male rats were maintained on a regimen of twice daily intragastric administration of ethanol or a calorifically equivalent sucrose solution for thirty days. A second control group received no intragastric solution and all groups received chow and water ad libitum. Parotid saliva elicited by pilocarpine was collected by unilateral duct cannulation. The parotid flow rate over the initial post-stimulatory five minute period was raised by 44% in ethanol-dosed rats and the salivary sodium concentration was also raised, in line with higher flow rate. There were no histopathological changes related to ethanol or sucrose dosing, but stereological analysis showed a 64% increase in the proportional volume of intralobular vascular tissue in ethanol-dosed rats. These quantified histological findings suggest that parotid intralobular haemodynamics may be altered after chronic ethanol-dosing and this may contribute to the hypersecretory response exhibited by the ethanol-dosed rats.