Effects of caffeine and 3-isobutyl-1-methylxanthine on voltage-activated potassium currents in vertebrate neurones and secretory cells.
Effects of caffeine and 3-isobutyl-1-methylxanthine on voltage-activated potassium currents in vertebrate neurones and secretory cells.
复制标题
咖啡因和 3-异丁基-1-甲基黄嘌呤对脊椎动物神经元和分泌细胞中电压激活钾电流的影响。
DOI：
10.1111/j.1476-5381.1996.tb15655.x
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发表时间：
1996
影响因子：
7.3
通讯作者：
Dryer,SE
中科院分区：
文献类型：
--
作者：
Reiser,MA;D'Souza,T;Dryer,SE
1The effects of caffeine and 3‐isobutyl‐1‐methylxanthine (IBMX) on voltage‐activated K+currents were examined by use of patch clamp recording techniques in dissociated chick autonomic ganglion neurones, chick pineal cells and rat anterior pituitary cells.2In chick ciliary ganglion neurones, caffeine (0.1–10 mM) produced a robust blockade of delayed rectifier K+currents (IDR). Blockade was rapid in onset and concentration‐ and voltage‐dependent. Caffeine produced greater inhibition with larger depolarizing voltage pulses. Similar inhibition ofIDRwas observed in excised outside‐out ‘maxi‐patches’ indicating a direct effect on the K+channels. Caffeine also inhibitedIDRin chick sympathetic neurones, chick pineal cells and rat anterior pituitary cells.3Application of 10 mM caffeine caused inhibition of transient A‐currents (IA) in chick ciliary ganglion neurones. Inhibition ofIAwas voltage‐dependent with greater inhibition observed at more positive command potentials. Application of 1 mM caffeine did not cause inhibition ofIA.4Application of 1 mM IBMX, a structural analogue of caffeine, caused inhibition ofIDRandIAin chick ciliary ganglion neurones. The voltage‐dependence of the inhibition of both currents was qualitatively different from that observed with caffeine. The inhibitory effects of 1 mM IBMX and 10 mM caffeine onIDRandIAwere additive.5Direct inhibition of voltage‐activated K+currents can potentially produce significant secondary effects on intracellular free Ca2+. These results indicate that caution must be used in the design and interpretation of experiments in which millimolar concentrations of caffeine or IBMX are used in pharmacological studies of intracellular Ca2+dynamics or other second messenger mechanisms.
