Lynge Jan, Schulte Gunnar, Nordsborg Nikolai, Fredholm Bertil B, Hellsten Ylva
Copenhagen Muscle Research Centre, Department of Human Physiology, Institute of Exercise and Sports Sciences, August Krogh Institute, Copenhagen University, Universitetsparken 13, Copenhagen Ø, DK-2100, Denmark.
Biochem Biophys Res Commun. 2003 Jul 18;307(1):180-7. doi: 10.1016/s0006-291x(03)01125-2.
The present study examined the existence of the adenosine A(1),A(2A), and A(2B) receptors and the effect of receptor activation on cAMP accumulation and protein phosphorylation in primary rat skeletal muscle cells. Presence of mRNA and protein for all three receptors was demonstrated in both cultured and adult rat skeletal muscle. NECA (10(-9)-10(-4)M) increased the cAMP concentration in cultured muscle cells with an EC(50) of (95% confidence interval)=15 (5.9-25.1) micro M, whereas CGS 21680 (10(-9)-10(-4)M) had no effect on cAMP accumulation. Concentrations of [R]-PIA below 10(-6)M had no effect on cAMP accumulation induced by either isoproterenol or forskolin. NECA resulted in phosphorylation of CREB with an EC(50) of (95% confidence interval)=1.7 (0.40-7.02) micro M, whereas ERK1/2 and p38 phosphorylation was unchanged. The results show that, although the A(1),A(2A), and A(2B) receptors are all present in skeletal muscle cells, the effect of adenosine on adenylyl cyclase activation and phosphorylation of CREB is mainly mediated via the adenosine A(2B) receptor.
本研究检测了大鼠原代骨骼肌细胞中腺苷A(1)、A(2A)和A(2B)受体的存在情况，以及受体激活对cAMP积累和蛋白磷酸化的影响。在培养的大鼠骨骼肌细胞和成年大鼠骨骼肌中均证实了这三种受体的mRNA和蛋白的存在。NECA（10(-9)-10(-4)M）可增加培养的肌细胞中的cAMP浓度，其EC(50)为（95%置信区间）=15（5.9-25.1）μM，而CGS 21680（10(-9)-10(-4)M）对cAMP积累无影响。低于10(-6)M的[R]-PIA浓度对异丙肾上腺素或福斯高林诱导的cAMP积累无影响。NECA导致CREB磷酸化，其EC(50)为（95%置信区间）=1.7（0.40-7.02）μM，而ERK1/2和p38磷酸化未改变。结果表明，虽然A(1)、A(2A)和A(2B)受体均存在于骨骼肌细胞中，但腺苷对腺苷酸环化酶激活和CREB磷酸化的作用主要通过腺苷A(2B)受体介导。
