9-(tetrahydro-2-furyl)-adenine and 3-bromo-7-nitroindazole

In this study we investigated the activity of the nitric oxide synthase (NOS) in parotid glands from rats with experimental periodontitis and controls.. Periodontitis was produced by a ligature placed around the cervix of the two lower first molar. Experiments were carried out 22 days after the ligature.. Ligation caused an increase in parotid NOS activity. The selective blocker of the inducible isoform of the enzyme partially inhibited its activity in parotid glands from rat with ligature. In controls, the activity was partially inhibited by the antagonists of the selective neural and endothelial isoforms. NOS activity in rats with ligature was cyclic adenosine monophosphate (cAMP)-dependent while in controls it was calcium-dependent. Prostaglandin E₂ concentration was increased in parotid gland from rats with ligature. The inhibitor of prostaglandin production, FR 122047, diminished both, prostaglandin production and NOS activity. In rats with ligature unstimulated amylase released is increased. Both, prostaglandin and NOS were involved in the increment of amylase release.. It can be concluded that in parotid glands from ligated rats, prostaglandin E₂ production is increased and, through cAMP accumulation, activates the inducible NOS isoform. The increment of nitric oxide production participates in the increase in basal amylase release.

Topics: Adenine; Amylases; Animals; Calcium; Cyclic AMP-Dependent Protein Kinase Catalytic Subunits; Cyclooxygenase Inhibitors; Dinoprostone; Disease Models, Animal; Egtazic Acid; Enzyme Inhibitors; Guanidines; Indazoles; Indomethacin; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; omega-N-Methylarginine; Organ Size; Ornithine; Parotid Gland; Periodontitis; Piperazines; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Wistar; Salivary Proteins and Peptides; Thiazoles

Stimulation of ovine airway epithelial cells with 10 microM ATP for 1 min at 25 degrees C transiently increased both cytoplasmic calcium (fura-2 epifluorescence microscopy) and ciliary beat frequency (CBF; differential interference contrast microscopy) with a similar time course. Identical purinergic stimulation of human airway epithelial cells at 25 or 35 degrees C, however, lead to an increase in CBF that outlasted the calcium transient at least 20 min. While a nitric oxide synthase inhibitor had no effect, pre-treatment of human cells with inhibitors of cAMP-dependent kinase (PKA), 10 microM myristoylated PKA-inhibitory peptide and 1 microM KT-5720, as well as an inhibitor of adenylyl cyclase, 1 mM SQ22536, blocked the prolonged, but not calcium-coupled CBF increase. Addition of PKA inhibitors after purinergic stimulation only partially reduced CBF from its elevated plateau. Prolonged CBF increases did not depend on adenosine production as 10 microM UTP had an effect similar to ATP and 8-sulphophenyl-theophylline did not block them. After increasing human CBF in a PKA-dependent manner to a stable plateau with forskolin (10 microM), ATP caused only a transient, calcium-coupled CBF increase. Calcium transients were necessary for both short-term and prolonged CBF changes as ATP failed to produce CBF increases after emptying calcium stores with 1 microM thapsigargin. These data suggest that in human, but not ovine airway epithelial cells, ATP-induced calcium transients activate a signalling cascade including adenylyl cyclase and PKA. The resulting prolonged CBF stimulation does not rely only on PKA activity, suggesting that the decay of CBF is influenced by ciliary phosphatase activity.

Topics: Adenine; Adenosine Triphosphate; Adenylyl Cyclase Inhibitors; Animals; Calcium; Cells, Cultured; Cilia; Colforsin; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP-Dependent Protein Kinases; Enzyme Inhibitors; Epithelial Cells; Extracellular Space; Humans; Indazoles; Intracellular Membranes; Nitric Oxide Synthase; Osmolar Concentration; Purines; Sheep; Time Factors; Trachea