Luminal space enlargement by carbachol in rat parotid intralobular ducts.
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.
Ohshima
Kazunobu
K
Department of Operative Dentistry, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Shiba
Yoshiki
Y
Hirono
Chikara
C
Sugita
Makoto
M
Iwasa
Yoshiko
Y
Shintani
Hideaki
H
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
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