title: Inhibition of calcium-calmodulin kinase restores nitric oxide production and signaling in submandibular glands of a mouse model of salivary dysfunction.
abstract: Nitric oxide is an intracellular and diffusible messenger of neurotransmitters involved in salivary secretion, as well as an inflammatory mediator in salivary gland diseases. It is synthesized by three different isoforms of nitric oxide synthase (NOS), each subject to a fine transcriptional, post-transcriptional and/or post-translational regulation. Our purpose was to study the possible mechanisms leading to NOS downregulation in submandibular glands of normal mice and in the nonobese diabetic (NOD) mouse model of salivary dysfunction with lower NOS activity. NOS activity and cGMP accumulation were determined by radioassays in submandibular glands of both mice in the presence of the protein kinase inhibitors KN-93 and bisindolylmaleimide. NOS I mRNA and protein expression and localization were assessed by RT-PCR, Western blot and immunohistochemistry. A downregulatory effect of calcium-calmodulin kinase II (CaMK II) on NOS activity in submandibular glands of both NOD and BALB/c mice was observed. Our results are consistent with a physiological regulation of NOS activity by this kinase but not by PKC in normal BALB/c mice. They are also supportive of a role for CaMK II in the lack of detectable NOS activity in submandibular glands of NOD mice. KN-93 also restored cGMP accumulation in NOD submandibular glands. The downregulation of NOS in NOD mice seems to be mainly mediated by this kinase rather than the result of a lower expression or different cellular localization of the enzyme. It was not related to different substrate or cofactors availability either.
authors.affiliation: Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires - CONICET, Argentina.
authors.forename: Florencia
authors.initials: F
authors.lastname: Rosignoli
authors.forename: Valeria
authors.initials: V
authors.lastname: Roca
authors.forename: Roberto
authors.initials: R
authors.lastname: Meiss
authors.forename: Nicolás
authors.initials: N
authors.lastname: Pregi
authors.forename: Claudia Pérez
authors.initials: CP
authors.lastname: Leirós
mesh_terms: D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D009569:Nitric Oxide / Q000096:biosynthesis*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D012466:Salivary Gland Diseases / Q000201:enzymology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D009569:Nitric Oxide; D017871:Calcium-Calmodulin-Dependent Protein Kinases