Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A correlation between reactions of the sympathoadrenal system and the activity of adenosine transformation enzymes in lymphocytes is demonstrated in the dynamics of metastatic Lewis carcinoma development in C57Bl mice. In the period when metastases arise a decrease in the adenosine deaminase activity in lymphoid cells of the thymus and spleen is accompanied by drop in the content of DOPA, noradrenalin and adrenalin in adrenals. At the late stages of the tumour process a decrease in the amount of these compounds in adrenals is accompanied by the diminution of the adenosine deaminase activity and by an increase in the 5'-nucleotidase activity in the thymus. Contrary changes are observed in spleen lymphocytes. The revealed disturbances may stimulate to a considerable extent the appearance and growth of metastases.
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PMID:[Enzymes of adenosine metabolism in lymphocytes and the functional state of the sympatho-adrenal system in tumor processes]. 301 May 22

Purified striatal synaptosomes were superfused continuously with L-[3,5-3H]tyrosine to measure simultaneously the synthesis ([3H]water formed during the conversion of [3H]tyrosine into [3H]DOPA) and the release of [3H]dopamine ([3H]DA). Glutamate (10(-3) M) and NMDA (10(-3) M, in the absence of Mg2+) stimulated the release of [3H]DA, but they reduced the efflux of [3H]water. This reduction of [3H]DA synthesis was blocked by 2-amino-5-phosphonovalerate indicating the involvement of NMDA receptors. Although D,L-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-4-propionate (AMPA) and kainate stimulated the release of [3H]DA, they did not affect its synthesis. The glutamate-evoked inhibition of [3H]DA synthesis was prevented when synaptosomes were superfused continuously with adenosine deaminase plus quinpirole, a treatment which markedly reduces the phosphorylation of tyrosine hydroxylase by cAMP dependent protein kinase. The opposite effects of glutamate on [3H]DA synthesis and release were mimicked by ionomycin (10(-6) M). It is proposed that both an activation of a cyclic nucleotide phosphodiesterase and a dephosphorylation of tyrosine hydroxylase linked to the influx of calcium through NMDA receptors is responsible for the inhibition of dopamine synthesis by glutamate and that calcineurin could play a critical role in these processes.
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PMID:Opposite presynaptic regulations by glutamate through NMDA receptors of dopamine synthesis and release in rat striatal synaptosomes. 791 26