L-NAME加强麻醉大鼠低血压诱发的催产素释放作用(英文)

L-NAME augments oxytocin secretion in response to hypotension in anesthetized rats:an implication of nitric oxide action

取戊巴比妥麻醉大鼠向侧脑室内分别注射一氧化氮 ( NO)合酶的底物 L-精氨酸和 NO合酶抑制剂NG-硝基 - L-精氨酸甲酯 ( L- NAME) ,用放射免疫法测定血浆中催产素 ( OT)水平。结果 :侧脑室内注射 L-精氨酸 ( 1 0 0 g/L,1 0 μL,n=8)和 L- NAME( 54.0 g/L,5μL,n=1 2 ) ,对 OT的基础分泌无明显影响 ;侧脑室内注射 5μL L- NAME(剂量 1 :2 7.0 g/L,n=9;剂量 2 :54.0 g/L,n=8) ,可进一步增强静脉输注硝普钠引起低血压所诱导的 OT分泌升高反应。结果表明 L- NAME能加强低血压诱发的 OT反射性释放作用 ,提示 NO可能是 OT反射性释放的抑制因子。

To detect the effect of nitric oxide (NO)on basal and reflex release of oxytocin (OT),L-arginine(the substrate of NO synthase )and N G nitro L-arginine methyl ester (L-NAME,NO synthase inhibitor)were intracerebroventricularly(icv)administrated into the pentobarbital anesthetized rats and the plasma OT level was detected with radioimmunoassay.Injection (icv) ofL arginine(100 g/L,10 μL,n=8)and L NAME (54 0 g/L,5 μL,n=12) had no significant effect on OT basal secretion.However,the elevated OT secretion in response to hypotension induced by intravenous infusion of sodium nitroprusside was dose dependently augmented by icv injection of 5 μL L NAME (dose 1:27 0 g/L,n=9;dose 2:54 0 g/L,n=8).The results indicate that L NAME does not change basal OT secretion,but enhances OT reflex secretion evoked by hypotension,which suggests that NO may act as an inhibitory factor on reflex release of OT. [