title: Luminal space enlargement by carbachol in rat parotid intralobular ducts.
abstract: Carbachol (CCh) enlarges the luminal space in rat parotid intralobular ducts, but the mechanism of their enlargement remains obscure. We investigated the involvement of intracellular calcium ions in the enlargement of luminal space by monitoring the luminal space under optical sectioning in a confocal laser scanning microscope using sulforhodamine B. Carbachol increased the intracellular concentration of calcium ions ([Ca2+]i) and the inside diameter without any change in the outside diameter. Removal of extracellular calcium ions modulated CCh-induced changes in [Ca2+]i to transient, but did not markedly inhibit the CCh-induced increase in the inside diameter. Additional loading of BAPTA (1,2-bis (o-aminophenoxy-ethane-n,n,n',n'-tetraacetic acid) in the duct cells suppressed CCh-induced changes. Diphenylamine-2-carboxylate (DPC), but not cytochalasin D, calmodulin inhibitor or nitric oxide synthase inhibitor profoundly suppressed CCh-induced changes. These results suggest that CCh induces enlargement of the luminal space through the activation of DPC-sensitive channels by the release of calcium ions from the intracellular pool.
authors.affiliation: Department of Operative Dentistry, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Ohshima
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Shiba
authors.forename: Chikara
authors.initials: C
authors.lastname: Hirono
authors.forename: Makoto
authors.initials: M
authors.lastname: Sugita
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Iwasa
authors.forename: Hideaki
authors.initials: H
authors.lastname: Shintani
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D002147:Calmodulin / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D015638:Cytochalasin D / Q000494:pharmacology; D045604:Extracellular Fluid / Q000378:metabolism; D005456:Fluorescent Dyes; D007424:Intracellular Fluid / Q000378:metabolism; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010306:Parotid Gland / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012235:Rhodamines; D018987:Salivary Ducts / Q000187:drug effects*; D062367:ortho-Aminobenzoates / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002147:Calmodulin; D018679:Cholinergic Agonists; D005456:Fluorescent Dyes; D019384:Nucleic Acid Synthesis Inhibitors; D012235:Rhodamines; D062367:ortho-Aminobenzoates; D015638:Cytochalasin D; C022027:lissamine rhodamine B; D002217:Carbachol; C001209:fenamic acid; D019001:Nitric Oxide Synthase; D002118:Calcium