INHIBITION BY LITHIUM OF GENTAMICIN-INDUCED RELEASE OF N-ACETYL-BETA-D-GLUCOSAMINIDASE IN RAT SUBMANDIBULAR SALIVA

1. The effects of gentamicin, lithium and concurrent treatment of thes e drugs on con centration of total protein and activity of the enzyme N-acetyl-beta-D-glucosaminidase (NAG) in rat submandibular saliva were studied. 2. Pure submandibular saliva was collected intraorally by mi cropolyethylene canula from anesthetized rats with the use of pilocarp ine as secretagogue. 3. Daily intraperitoneal injection of gentamicin (50 mg kg/day) for 5 consecutive days caused a marked increase in tota l protein concentration and the NAG activity. 4. Chronic treatment of rats for 10 days with lithium chloride solution (1,200 mg/l) caused a significant decrease in total protein concentration but did not affect the NAG activity. 5. Concurrent treatment of lithium with gentamicin caused the total protein concentration and the NAG activity of submand ibular saliva to reach to those of controls. 6. In this regard, the pr otective effects of lithium may be due to interference of this ion wit h the phosphoinositide cycle. (C) 1997 Elsevier Science Inc.