Reversed effect of caffeine on non-contractile and contractile Ca2+ mobilization operated by acetylcholine receptor in mouse diaphragm muscle.
Caffeine effects on contractile and acetylcholine receptor-related non-contractile Ca2+ mobilization were investigated in phrenic nerve-diaphragm muscles of mice with neostigmine. Caffeine enhanced at 0.25-5 mM, and decreased at 7-20 mM the total amount of contractile Ca(2+)-aequorin luminescence (Ca2+ transients), but only decreased at 2-10 mM non-contractile Ca2+ transients. Pretreatment with formamide (2 M for 30 min) abolished contractile Ca2+ transients, but did not affect non-contractile ones. These results suggest that non-contractile Ca2+ mobilization is not due to direct Ca2+ release from sarcoplasmic reticulum, but due to direct modulation by nicotinic acetylcholine receptor.
Kimura
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I
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Kondoh
T
T
Tsuneki
H
H
Kimura
M
M
D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D003964:Diaphragm / Q000378:metabolism; D005559:Formamides / Q000494:pharmacology; D008297:Male; D051379:Mice; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism*; D009388:Neostigmine / Q000494:pharmacology; D011950:Receptors, Cholinergic / Q000502:physiology*; D012433:Ryanodine / Q000494:pharmacology
D005559:Formamides; D011950:Receptors, Cholinergic; D012433:Ryanodine; D009388:Neostigmine; D002110:Caffeine; C031066:formamide; D002118:Calcium