Change of Cyclic AMP Level in Synaptosomes from Cerebral Cortex; Increase by Adenosine Derivatives |
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Authors: | Kazuo Kobayashi Yoichiro Kuroda Masanori Yoshioka |
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Institution: | Department of Neurochemistry, Tokyo Metropolitan Institute for Neurosciences, Fuchu City, Tokyo 183;Faculty of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan |
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Abstract: | The endogenous level of cyclic AMP in incubated synaptosomes from cerebral cortex of guinea pigs was investigated after the addition of various agents to the incubation medium. It appeared that the synaptosomal suspension already contained exogenous adenosine. Preincubation with theophylline or with adenosine deaminase (ADase) decreased both the exogenous level of adenosine and the intrasynaptosomal level of cyclic AMP. The level of cyclic AMP was reincreased by the addition of adenosine agonists, especially 2-chloroadenosine. This increase was antagonized by deoxyadenosine and was not inhibited by dipyridamole. These results suggest that the adenosine derivatives in the synaptic cleft regulate the level of cyclic AMP in nerve terminals through adenosine receptor on the presynaptic membrane. ADP, ATP, dopamine, and histamine also stimulate the formation of cyclic AMP in the ADase-treated synaptosomes. |
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Keywords: | Cyclic AMP Adenosine Synaptosome Presynaptic receptor Cerebral cortex |
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