摘要
目的研究蛋白激酶A(PKA)在大鼠肾上腺髓质嗜铬细胞分泌儿茶酚胺(CA)中的作用机制。方法利用全细胞膜片钳技术,在维持电压-70 mV的条件下,给予细胞40 ms,从-60mV到+60 mV的序列除极方波,阶跃10 mv,引导出钙通道电流(ICa),观察各种不同浓度PKA激动剂对大鼠嗜铬细胞ICa的影响。结果100μmol/L dcAMP对大鼠嗜铬细胞内ICa作用不明显;1和10 μmol/L Forskolin对ICa有明显抑制作用,灌洗细胞10 min对ICa峰值抑制率分别为(15.8±2.0)％和(29.7±2.0)％。结论PKA在大鼠肾上腺髓质嗜铬细胞CA分泌过程中的作用不明显。Forskolin能够明显抑制大鼠嗜铬细胞ICa,从而抑制CA的分泌,其机制可能是对钙通道的直接作用。
Objective To study the effect of protein kinase (PKA) on catelamine (CA) secretion in rat adrenal chromaffin cells. Methods By using the whole-cell patch-clamp technique, the effect of different kinds of PKA agonists on Ca2 ± influx (ICa) in rat chromaffin cells was studied. The effects of different kinds of Ca2+ channel antagonists on ICa were observed by 40 ms depolaring pulse applied from a holding potential of -70 mV in 10 mV steps up to ± 60 mV. Results 100μmol/L dibutyryl cyclic AMP ( dcAMP) had no significant effect on Ica in rat chromaffin cells. ICa could be obviously inhibited by using 1μmol/L and 10 /μmol/L forskolin perfusing cells for 10 min. The inhibition rates of peak value were (15.8±2.0)% and (29.7 ± 2.0)% respectively.Conclusion PKA has no significant effect on CA secretion in rat adrenal chromaffin cells. Forskolin inhibits CA release in chromaffin cells obviously. The mechanism of forskolin may be direct effect on calcium channel.
出处
《中华实验外科杂志》
CAS
CSCD
北大核心
2003年第2期149-150,共2页
Chinese Journal of Experimental Surgery
