Effects of rubidium on the secretory function of the rat submandibular gland

Effects of rubidium chloride (1200 mg/L drinking water) treatment for 10 d on rat submandibular saliva composition were examined in, this study. Both submandibular ducts were calculated intraorally with polyethylene tubes, and pure saliva was collected from anesthetized rubidium-treated and control rats using pilocarpine as a secretagogue. Saliva protein and calcium concentrations were found to be significantly (p < .05) increased in rubidium-treated groups. N-acetyl-beta-D-glucosaminidase (NAG) is one of the sensitive hydrolytic lysosomal enzymes that cart be released after submandibular gland damage. The secretion, of NAG in saliva increased significantly (p < .01) after rubidium treatment. Salivary flow rate, normalized for gland weight, was also affected by rubidium treatment as there was a significant (p < .01) reduction of flow rate in rubidium-exposed rats. There is no obvious basis for these alterations in saliva protein and calcium content and in pow rate induced with rubidium, but possible mechanisms such as interaction with two major transduction mechanisms operative in salivary gland acinar cells (generation of CAMP or breakdown of plasma membrane polyphosphoinositides) are suggested. Also, considering increased NAG secretion into saliva induced by rubidium, it is proposed that rubidium has a toric effect in rat submandibulary gland cells. Finally our results indicate rubidium acts las a partial antagonist) to lithium in submandibulary glands.