Nitric oxide participation in cholinergic effect of IFNg in salivary amylase secretion

ESPAÑOL ALEJANDRO; SALES MARÍA

San Luis, Argentina

Congreso; 31 Reunión Anual de la Sociedad Argentina de Investigación Odontológica- International Association for Dental Research; 1998

Cytokines (CK) are an important group of secreted protein mediators with regulate many aspects of cell growth, activation and other effector functions. They have major effects on the outcome on inflammatory and immune responses. One of the best studies is IFNg and it has been stated as a pleiotropic CK. Among non immunologic functions that has been studies we have demonstrated that IFNg  activates muscarinic cholinergic receptors (mAchR) increasing intestinal motility. Taking into account that CK are released from infiltrating cells in inflamed tissues, we are investigate the role of IFNg in the physiology of murine submandibular glands (SMG) either in control or in locally inflamed animals (LIA). IFNg increased amylase secretion (AS) in SMG (mg maltose released/min. g.w.w.tis.) (basal:1.18±0.28, n=5; IFNg 10 U/ml:2.30±0.12, n=5). The effects was totally blocked by genistein (30 mg/ml) and staurosporine (2x10-9M) and partially inhibited by atropine (10-6M) and L-NAME (10-4M), pointing to mAchR and nitric oxide synthase (NOS) participation in AS. Nitrite production was: basal 61.13±3.15 (n=5) IFNg 10  U/ml:148.41±4.40 (n=4). In LIA the inhibition in AS could not be reverted by IFNg (LPS-basal:0.68±0.16, n=5; IFNg 10 U/ml: 0.88±0.15, n=4) and nitrite production is dramatically diminished by IFNg (LPS-basal: 96.69±9.21, n=6; IFNg 10 U/ml: 8.32±2.25, n=4). We can conclude that IFNg stimulates AS mediated by mAchR and NOS activation in SMG. In LIA, NO hiperproduction modifies the SMG microenvironment, inhibiting that stimulation.