<b>α1-Adrenoceptors relate Ca</b><sup><b>2+</b></sup><b> modulation and protein secretions in rat lacrimal </b><b>gland </b>
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- IKEDA-KUROSAWA Chika
- Department of Anatomy (Cell Biology), Iwate Medical University Department of Ophthalmology, School of Medicine, Iwate Medical University
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- HIGASHIO Hironori
- Department of Chemistry, Center for Liberal Arts and Sciences, Iwate Medical University
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- NAKANO Masato
- Department of Anatomy (Cell Biology), Iwate Medical University
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- OKUBO Masatoshi
- Department of Anatomy (Cell Biology), Iwate Medical University Department of Ophthalmology, School of Medicine, Iwate Medical University
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- SATOH Yoh-ichi
- Department of Medical Education, Iwate Medical University
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- KUROSAKA Daijiro
- Department of Ophthalmology, School of Medicine, Iwate Medical University
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- SAINO Tomoyuki
- Department of Anatomy (Cell Biology), Iwate Medical University
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Abstract
Noradrenaline (NA) is a catecholamine with multiple roles including as a hormone and a neurotransmitter. Cellular secretory activities are enhanced by adrenergic stimuli as well as by cholinergic stimuli. The present study aimed to determine which adrenoceptors play a role in controlling intracellular calcium ion ([Ca2+]i) level in acinar cells of rat lacrimal glands. Expression of mRNA for adrenoceptor subtypes in the acinar cells was assessed using RT-PCR. All types except α2c, β1, and β3 were detected. NA induced a [Ca2+]i increase with a biphasic pattern in the acinar cells. Removal of extracellular Ca2+ and use of Ca2+-channel blockers did not inhibit the NA-induced [Ca2+]i increases. In contrast, U73122 and suramin almost blocked these increases. The α1-adrenoceptor agonist phenylephrine induced a strong increase in [Ca2+]i. However, clonidine and isoproterenol failed to induce a [Ca2+]i increase. The peroxidase activity was quantified as a measure of mucin secretion. Ca2+-dependent exocytotic secretion of peroxidase was detected in rat lacrimal glands. The RT-PCR results showed that MUC1, MUC4, MUC5AC, MUC5B, and MUC16 were expressed in acinar cells. These findings indicated that NA activates α1-adrenoceptors, which were found to be the main receptors in Ca2+-related cell homeostasis and protein (including mucin) secretion in lacrimal glands.
Journal
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- Biomedical Research
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Biomedical Research 36 (6), 357-369, 2015
Biomedical Research Press