Tachykinins induce a [Ca2+]i rise in the acinar cells of feline tracheal submucosal gland.
The intracellular Ca2+ concentration ([Ca2+]i) of acinar cells of isolated submucosal glands from trachea was measured using a fluorescent dye, Fura-2. Neurokinin A (NK-A) produced a sustained rise in [Ca2+]i in a dose-dependent manner, reaching a response of 500 to 600% of the prior baseline value at 10(-6) or 10(-5) M, and the NK-A evoked [Ca2+]i was significantly higher than that by substance P (SP) at similar concentrations. NK-B did not induce significant increases in [Ca2+]i. In a Ca(2+)-free solution, NK-A produced a transient rise in [Ca2+]i, which returned to the baseline within 3 min. Mucus glycoprotein (MGP) secretion, estimated by measuring trichloroacetic-acid (TCA) precipitable glycoconjugates, was stimulated by NK-A or SP. These findings indicate that tachykinins produce a rise in [Ca2+]i by both entry from the extracellular solution and release from intracellular storage, probably by NK-2 receptor stimulation, and stimulate MGP secretion from airway submucosal glands.
Nagaki
M
M
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Ishihara
H
H
Shimura
S
S
Sasaki
T
T
Takishima
T
T
Shirato
K
K
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002415:Cats; D005088:Exocrine Glands / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016257:Fura-2; D006023:Glycoproteins / Q000378:metabolism; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D009077:Mucins / Q000378:metabolism; D015288:Neurokinin A / Q000494:pharmacology; D015287:Neurokinin B / Q000494:pharmacology; D064729:Neurokinin-1 Receptor Antagonists; D010456:Peptides, Cyclic / Q000494:pharmacology; D018041:Receptors, Neurokinin-2 / Q000037:antagonists & inhibitors; D013373:Substance P / Q000037:antagonists & inhibitors / Q000494:pharmacology; D015320:Tachykinins / Q000494:pharmacology*; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D006023:Glycoproteins; D007202:Indicators and Reagents; D009077:Mucins; D064729:Neurokinin-1 Receptor Antagonists; D010456:Peptides, Cyclic; D018041:Receptors, Neurokinin-2; D015320:Tachykinins; C075570:FK 224; D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B; D002118:Calcium; D016257:Fura-2