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

The present study investigated the role of adenosine in the stimulatory action of paeoniflorin on in vitro glucose transport. Paeoniflorin increased the uptake of a radiolabeled, non-metabolizable glucose derivative into isolated white adipocytes of Wistar rat in a concentration-dependent manner and this action was abolished by the antagonist, 8-cyclopentyltheophylline, at concentrations sufficient to block the adenosine A 1 receptor. However, paeoniflorin failed to displace the binding of [3H]-8-cyclopentyl-1,3-dipropylxanthine in the isolated cerebrocortex of Wistar rat. Direct activation of the adenosine A 1 receptor does not seem to be responsible for the action of paeoniflorin. The stimulatory effect of paeoniflorin on radioactive glucose uptake was abolished in isolated rat white adipocytes pre-incubated with the adenosine deaminase at concentrations sufficient to metabolize endogenous adenosine. Mediation of endogenous adenosine in the action of paeoniflorin was further supported by the assay of adenosine released into the medium from rat white adipocytes incubated with paeoniflorin. These findings suggest that paeoniflorin could induce the release of adenosine from isolated rat white adipocytes and the released adenosine may activate the adenosine A 1 receptor to enhance glucose uptake.
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PMID:Stimulatory effect of paeoniflorin on adenosine release to increase the glucose uptake into white adipocytes of Wistar rat. 1270

The effects of paeoniflorin, a glycoside isolated from the root of Paeonia lactiflora, on ion currents in a mouse neuroblastoma and rat glioma hybrid cell line, NG108-15 were investigated. Paeoniflorin (1-300 microM) reversibly produced an inhibition of L-type voltage-dependent Ca2+ current (I(Ca,L)) in a concentration-dependent manner. Paeoniflorin caused no change in the overall shape of the current-voltage relationship of I(Ca,L). The IC50 value of paeoniflorin-induced inhibition of I(Ca,L) was 14 microM. However, neither adenosine deaminase (1 U/ml) nor 8-cyclopentyl-1, 3-dipropylxanthine (10 microM) could reverse the inhibition by paeoniflorin of I(Ca,L). Paeoniflorin (30 microM) shifted the steady-state inactivation curve of I(Ca,L) to more negative membrane potentials by approximately -10 mV. It also prolonged the recovery of I(Ca,L). The inhibitory effect of paeoniflorin on I(Ca,L) exhibited tonic and use-dependent characteristics. Paeoniflorin could effectively suppress I(Ca,L) evoked by action potential waveforms. Paeoniflorin at a concentration of 30 microM produce a slight inhibition of voltage-dependent Na+ current and delayed rectifier K+ current. Under current-clamp configuration, unlike adenosine, this compound decreased the firing of action potentials. Taken together, this study indicates that paeoniflorin can block L-type Ca2+ channels in NG108-15 cells in a mechanism unlinked to the binding to adenosine receptors. The effects of paeoniflorin on ion currents may partly, if not entirely, contribute to the underlying mechanisms through which it affects neuronal or neuroendocrine function.
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PMID:Inhibitory action of L-type Ca2+ current by paeoniflorin, a major constituent of peony root, in NG108-15 neuronal cells. 1624 10