Ulianich Luca, Elia Maria Giovanna, Treglia Antonella Sonia, Muscella Antonella, Di Jeso Bruno, Storelli Carlo, Marsigliante Santo
Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, Università degli Studi di Lecce, Ecotekne, Via Provinciale per Monteroni, 73100 Lecce, Italy.
J Endocrinol. 2006 Sep;190(3):641-9. doi: 10.1677/joe.1.06455.
In PC Cl3 cells, a continuous, fully differentiated rat thyroid cell line, P2Y(2) purinoceptor activation provoked a transient increase of Ca(2+), followed by a decreasing sustained phase. The alpha and beta1 protein kinase C (PKC) inhibitor Gö6976 decreased the rate of decrement to the basal Ca(2+) level and increased the peak of Ca(2+) entry of the P2Y(2)-provoked Ca(2+)transients. These effects of Gö 6976 were not caused by an increased permeability of the plasma membrane, since the Mn(2+) and Ba(2+) uptake were not changed by Gö 6976. Similarly, the Na(+)/Ca(2+) exchanger was not implicated, since the rate of decrement to the basal Ca(2+) level was equally decreased in physiological and Na(+)-free buffers, in the presence of Gö 6976. On the contrary, the activity of the sarcoplasmic-endoplasmic reticulum Ca(2+)ATPase (SERCA) 2b was profoundly affected by Gö 6976 since the drug was able to completely inhibit the stimulation of the SERCA 2b activity elicited by P2-purinergic agonists. Finally, the PKC activator phorbol myristate acetate had effects opposite to Gö 6976, in that it markedly increased the rate of decrement to the basal Ca(2+) level after P2Y(2) stimulation and also increased the activity of SERCA 2b. These results suggest that SERCA 2b plays a role in regulating the sustained phase of Ca(2+) transients caused by P2Y(2) stimulation.
在PC Cl3细胞（一种连续的、完全分化的大鼠甲状腺细胞系）中，P2Y(2)嘌呤受体激活引发细胞内钙离子浓度（Ca(2+)）短暂升高，随后进入持续降低阶段。α和β1蛋白激酶C（PKC）抑制剂Gö6976降低了Ca(2+)降至基础水平的衰减速率，并增加了P2Y(2)引发的Ca(2+)瞬变中Ca(2+)内流的峰值。Gö 6976的这些作用并非由质膜通透性增加所致，因为Gö 6976并未改变锰离子（Mn(2+)）和钡离子（Ba(2+)）的摄取。同样，钠钙交换体也未涉及其中，因为在存在Gö 6976的情况下，无论是在生理缓冲液还是无钠缓冲液中，Ca(2+)降至基础水平的衰减速率均同等降低。相反，Gö 6976对肌浆网-内质网Ca(2+)ATP酶（SERCA）2b的活性有显著影响，因为该药物能够完全抑制P2-嘌呤能激动剂引发的SERCA 2b活性刺激。最后，PKC激活剂佛波醇肉豆蔻酸酯的作用与Gö 6976相反，它显著增加了P2Y(2)刺激后Ca(2+)降至基础水平的衰减速率，并且还增加了SERCA 2b的活性。这些结果表明，SERCA 2b在调节由P2Y(2)刺激引起的Ca(2+)瞬变的持续阶段中发挥作用。
