Intracellular calcium concentration of acinar cells in feline tracheal submucosal glands.
We measured the intracellular free calcium ion concentration [( Ca2+]i) of acinar cells in isolated feline tracheal submucosal glands in response to secretagogues using the Ca2(+)-sensitive fluorescent dye fura-2. The secretagogues included cholinergic, adrenergic agonists, substance P (SP), and vasoactive intestinal polypeptide (VIP) which induce mucus glycoprotein secretion from feline tracheal submucosal glands. Methacholine (MCh) produced a significant increase in [Ca2+]i of up to 9.8 times that of control in a dose-dependent fashion at concentrations of 10(-8) to 10(-3) M. [Ca2+]i increase by MCh reached a peak within 30 s after stimulation and thereafter showed a sustained rise. In Ca2(+)-free medium, MCh produced an initial transient rise, which was less than 30% of that in a Ca2(+)-containing solution, and which lasted for 60 s with no prolonged sustained rise in [Ca2+]i. Atropine abolished MCh-evoked [Ca2+]i increase. Phenylephrine and SP produced a prolonged increase in [Ca2+]i without an initial transient increase. Phenylephrine (up to 10(-4) M) evoked an increase in [Ca2+]i by up to 240% that of control, which was abolished by prazosin. SP (up to 10(-4) M) also evoked an increase in [Ca2+]i by 155% that of control, which was abolished by atropine. By contrast, both isoproterenol (up to 10(-5) M) and VIP (up to 10(-5) M) failed to alter [Ca2+]i. These findings indicate that the mucus glycoprotein secretion evoked by muscarinic cholinergic, alpha-adrenergic agonist or SP can be mediated by intracellular Ca2+, whereas that by beta-adrenergic agonists or VIP cannot.
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
H
H
Ishihara
S
S
Shimura
M
M
Sato
T
T
Masuda
N
N
Ishide
M
M
Miura
T
T
Sasaki
H
H
Sasaki
T
T
Takishima
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002415:Cats; D003902:Detergents / Q000494:pharmacology; D005088:Exocrine Glands / Q000187:drug effects / Q000378:metabolism*; D005990:Glycerol / Q000031:analogs & derivatives / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D016210:Methacholine Chloride / Q000494:pharmacology; D009093:Mucus; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D003902:Detergents; D006023:Glycoproteins; D016210:Methacholine Chloride; D010656:Phenylephrine; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; C000515:cremophor EL; D005990:Glycerol; D002118:Calcium