Regulation of beta-agonist-induced secretion of amylase from rat parotid acini by K^+-channels

本文结合β-受体功能研究了K~+通道在调节大鼠腮腺腺泡淀粉酶分泌中的作用。结果表明，增加细胞外K~+浓度或加入K~+通道阻滞剂可促进淀粉酶的分泌。在几种K~+通道阻滞剂中，四乙基铵、阿帕明和河豚毒素分别有效地使淀粉酶的分泌增加48%、69%和84%。格列本脲无作用。低浓度去甲肾上腺素(10^~(-7)~(-7)~(-1)M)使淀粉酶的分泌增加154%，并与四乙基铵联合使用，产生371%的刺激。四乙基铵与低浓度的卡巴胆碱(10~(-1))联合使用对淀粉酶的分泌有协同作用。去甲肾上腺素(10^~(-6)-6&gt；M)对去甲肾上腺素(10^；-6&gt；M)的分泌无协同作用。去甲肾上腺素(10^；-6&gt；M)和吗啡(10^&lt；-4&gt；M)可使去甲肾上腺素诱导的AIM分泌增加313%，而K~(+)离子载体10^~(-3)-3&gt；M使之减少116%。以上结果提示，去甲肾上腺素对卡巴胆碱(10^&lt；-5&gt；M)和吗啡(10^&lt；-4&gt；M)的分泌无影响。生长抑素(10^&lt；-5&gt；M)和吗啡(10^&lt；-4&gt；M)对去甲肾上腺素诱导的AIM分泌也有抑制作用-去甲肾上腺素激活腮腺腺泡淀粉酶分泌过程中的K~+通道。

The involvement of K^+ channels in regulating secretion of amylase from isolated rat parotid acini was studied in conjunction with beta-adrenoceptor function.It was observed that increasing the concentration of extracellular K^+ or adding K^+ channel blockers enhanced the secretion of amylase.Among several K^+ channel blockers, tetraethylammonium, apamin and charybdotoxin were effective to enhance secretion by 48, 69, and 84%, respectively.Glibenclamide was without effect.A low concentration of noradrenaline (10^<-7> M) enhanced secretion by 154% and its simultaneous application with tetraethylammonium gave a synergistic effect, producing 371% stimulation.Combination of tetraethylammonium and a low concentration of carbachol (10^<-6> M) did not give the synergistic effect.Noradrenaline at the concentration of 10^<-6> M enhanced secretion by 313% and this was reduced to 116% by 10^<-3> M valinomycin, a K^+ ionophore.Valinomycin was without effect on carbachol (10^<-5> M)-induced secretion.Somatostatin (10^<-5> M) and morphine (10^<-4> M) also reduced noradrenaline-induced scretion of aimylase.These results suggested the regulation of Ca^<2+> -activated K^+ channels by noradrenaline in amylase secretory processes in parotid acini.