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ADENOSINE UPTAKE BY CHOLINERGIC SYNAPTOSOMES FROM TORPEDO ELECTRIC ORGAN
Author(s) -
Meunier F. M.,
Morel N.
Publication year - 1978
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1978.tb00119.x
Subject(s) - adenosine , torpedo , electric organ , cholinergic , cholinergic system , dipyridamole , chemistry , synaptosome , biophysics , biochemistry , pharmacology , medicine , biology , endocrinology , membrane , acetylcholine receptor , receptor
Pure cholinergic synaptosomes prepared from the electric organ of Torpedo are able to take adenosine up efficiently and convert it to ATP. The apparent K m of the adenosine uptake is 2.4 μM and the V m : 518 pmol/30′/mg prot. The uptake system exhibits a high specificity towards adenosine, as shown by the lack of competition with analogues. Tubercidin blocks the uptake competitively and dipyridamole is a very potent non competitive inhibitor ( K i = 4 × 10 ‐8 M). Considering that during nerve activity ATP is released extracellularly and can modulate transmitter release, the physiological significance of adenosine uptake is discussed as a possible mechanism to terminate the ATP action.