1.Fluid and amylase secretion by perfused parotid gland: physio-morphological approach.
Masataka MURAKAMI ; Keiichi YOSHIMURA ; Hiroshi SUGIYA ; Akihisa SEGAWA ; Felice LOFFREDO ; Francesca TESTA-RIVA ; Alessandro RIVA
Journal of Korean Medical Science 2000;15(Suppl):S38-S39
Whole gland perfusion technique was applied to rat parotid glands to assess whether amylase affects fluid secretion. Control perfusion without any secretagogue evoked no spontaneous secretion. Carbachol (CCh 1 microM) induced both amylase and fluid secretion with distinctive kinetics. Fluid secretion occurred constantly around 60 microL/g-min, whereas amylase secretion exhibited an initial peak, followed by a rapid decrease to reach a plateau. Isoproterenol (Isop 1 microM) alone did not induce fluid secretion although it evoked amylase secretion as measured in isolated perfused acini. Addition of Isop during CCh stimulation evoked a rapid and large rise in amylase secretion accompanied by small increase in oxygen consumption. Morphological observations carried out by HR SEM and TEM revealed exocytotic profiles following Isop stimulation. CCh stimulation alone seldom showed exocytotic profiles, suggesting a low incidence of amylase secretion during copious fluid secretion. Combined stimulation of CCh and Isop induced both vacuolation and exocytosis along intercellular canaliculi. These findings suggest that control of salivary fluid secretion is independent of the amylase secretion system induced by CCh and/or Isop.
Amylases/metabolism*
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Animal
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Carbachol/pharmacology
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Cholinergic Agonists/pharmacology
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In Vitro
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Isoproterenol/pharmacology
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Male
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Microscopy, Electron
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Microscopy, Electron, Scanning
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Oxygen Consumption/physiology
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Oxygen Consumption/drug effects
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Parotid Gland/ultrastructure
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Parotid Gland/secretion*
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Parotid Gland/enzymology*
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Perfusion
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Rats
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Rats, Wistar
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Saliva/metabolism*
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Sympathomimetics/pharmacology
2.Riluzole Selective Antioxidant Effects in Cell Models Expressing Amyotrophic Lateral Sclerosis Endophenotypes
Gessica SALA ; Alessandro AROSIO ; Elisa CONTI ; Simone BERETTA ; Christian LUNETTA ; Nilo RIVA ; Carlo FERRARESE ; Lucio TREMOLIZZO
Clinical Psychopharmacology and Neuroscience 2019;17(3):438-442
OBJECTIVE: Until recently, riluzole was the only drug licensed for amyotrophic lateral sclerosis (ALS). In spite of its efficacy, the mechanism of action remains elusive, and both blocking of glutamate release and antioxidant properties have been postulated. Here we characterized human SH-SY5Y neuroblastoma cell lines, taking advantage of their insensitivity to excitotoxic insults, in order to selectively assess the presence of a direct antioxidant effect of riluzole. METHODS: SH-SY5Y cells, either parental or overexpressing the G93A SOD1 mutation, were exposed for 24 hours to the selected stimuli. RESULTS: Riluzole (1–10 μM) was able to counteract the effects of H₂O₂ exposure (200 μM/24 hr), limiting both cell death and whole-cell reactive oxygen species (ROS) increase. The same experiments were repeated using SH-SY5Y cells carrying the familial ALS-related G93A-SOD1 mutation and constitutively expressing two-fold increased whole-cell ROS levels with respect to wild-type cells: riluzole was ineffective in this paradigm. Analogously, riluzole was ineffective in preventing cell death induced by exposing SH-SY5Y cells to 3-morpholino-sydnonimine (SIN-1, 1.5 mM/24 hr), a reactive nitrogen species (RNS) donor. CONCLUSION: Our data support a direct antioxidant action of riluzole. Furthermore, the lack of efficacy of riluzole observed in the SOD1 cell model mirrors the lack of efficacy already demonstrated in cognate mouse models of ALS, plausibly reflecting differences in the underlying pathogenic mechanisms. Finally, riluzole inefficacy against nitrosative stress might support the idea that a combined therapeutic intervention may result more effective in ALS patients, as in the case of co-administration of edaravone, a drug known to reduce RNS.
Amyotrophic Lateral Sclerosis
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Animals
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Antioxidants
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Cell Death
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Cell Line
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Endophenotypes
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Glutamic Acid
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Humans
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Mice
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Neuroblastoma
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Parents
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Reactive Nitrogen Species
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Reactive Oxygen Species
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Riluzole
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Tissue Donors