Adenosine transport into guinea-pig synaptosomes.
Kinetics for transport of adenosine into guinea-pig neocortex synaptosomes were studied by incubating them with [14C]adenosine for up to 30 s. The apparent Km value of the high-affinity transport system for adenosine was 21.1 microM and the Vmax value was 257.3 pmol/min/mg protein. The transport system was inhibited by both compounds structurally related (compounds 554 and 555) and unrelated (dipyridamole) to adenosine. Because electrically stimulated synaptosomes release up to 1.5% of the adenosine derivative content per min, the physiological significance of adenosine uptake is discussed as a possible mechanism to compensate for the loss of adenine nucleotides from synaptosomal preparations.
D000227:Adenine Nucleotides / Q000096:biosynthesis; D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D001693:Biological Transport, Active; D002540:Cerebral Cortex / Q000378:metabolism*; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D011687:Purines / Q000096:biosynthesis; D013574:Synaptosomes / Q000378:metabolism*; D013816:Thermodynamics
D000227:Adenine Nucleotides; D011687:Purines; D000241:Adenosine