Adenosine increases an internal calcium store in the smooth muscle of guinea-pig taenia coli.
The effect of adenosine on an internal calcium store which can be released by carbachol to produce a transient contraction in Ca2+-free solution was investigated in the taenia depolarized by high K+. The carbachol contraction in Ca2+-free solution was increased by the preceding application of adenosine (3 X 10(-5) to 10(-3) M), an effect which was mimicked by ATP, but not by the slowly degradable analog alpha, beta-methylene ATP. The P1-purinoceptor antagonist 8-phenyltheophylline inhibited the increase caused by adenosine without modifying the carbachol contraction in controls. It is concluded that stimulation of an extracellular P1-purinoceptor increases an internal store of calcium, which might contribute to the relaxation induced by adenosine in the taenia.
Frischknecht
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R
Ferrero
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JD
D000241:Adenosine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000187:drug effects; D011983:Receptors, Purinergic
D017981:Receptors, Neurotransmitter; D011983:Receptors, Purinergic; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D000241:Adenosine; D002118:Calcium