胍丁胺抑制大鼠颈动脉窦压力感受器活动  

Agmatine inhibits the afferent activity of carotid baroreceptor in rats

作　　者：秦晓梅[1] 范振中[1] 何瑞荣[1] 

机构地区：[1]河北医科大学基础医学研究所生理室,石家庄050017

出　　处：《生理学报》2001年第2期137-141,共5页Acta Physiologica Sinica

摘　　要：在麻醉大鼠隔离灌流颈动脉窦区条件下 ,记录窦神经传入放电 ,观察胍丁胺 (agmatine ,Agm)对动脉压力感受器活动的影响。结果如下 :(1)以 1mmol/LAgm隔离灌流大鼠颈动脉窦区时 ,窦内压 窦神经传入放电积分(ISP ISNA)关系曲线向右下方移位 ,曲线的最大斜率 (PS)降低 ,窦神经传入放电最大积分值 (PIV)减小。再分别以5、10mmol/LAgm灌流时 ,机能曲线向右下方移位更为明显 ,PS及PIV降低更加明显 ,从而表明Agm抑制压力感受器活动且呈剂量依赖性。 (2 )α2 肾上腺素受体 (α2 adrenoceptor,α2 AR)和咪唑啉受体 (IR)的阻断剂咪唑克生 (0 1mmol/L)可阻断Agm的上述效应。 (3)预先灌流α2 AR阻断剂育亨宾 (15 μmol/L)可部分阻断Agm的抑制效应。 (4 )预先灌流Ca2 +通道激动剂BayK 86 44 (5 0 0nmol/L)亦可取消Agm对窦神经传入放电的影响。以上结果表明 ,Agm对颈动脉窦压力感受器活动有抑制作用 ,此作用由IR和α2 AR介导 ,并与颈动脉窦压力感受器活动时Ca2The effect of agmatine (Agm) on the carotid baroreceptor activity was examined in 24 anesthetized rats with perfused isolated carotid sinus by recording sinus nerve afferent discharges. The results are as follows. (1) By perfusing with 1 mmol/L Agm, the functional curve for the intrasinus pressure (ISP)[WT5”BZ]integral of sinus nerve activiy (ISNA) relation was shifted to the right and downward with decreases in peak slope (PS) and peak integral value of carotid sinus afferent discharge (PIV). By perfusing with high concentrations of Agm (5 and 10 mmol/L), the curves were shifted to the right and downward further with marked decreases of PS and PIV. These results showed that Agm exerted an inhibitory action on the baroreceptor activity in a dose dependent manner. (2) The Agm induced decrease in sinus nerve afferent activity was eliminated by pretreatment with IR and α 2 AR blocker idazoxan (0.1 mmol/L). (3) Selective α 2 AR blocker yohimbine (15 μmol/L) partly abolished the inhibitory effect of Agm on baroreceptor. (4) Preperfusing with Bay K 8644 (500 nmol/L), an agonist of calcium channels, also eliminated the effect of Agm on carotid baroreceptor activity. These results indicate that Agm exerts an inhibitory action on carotid baroreceptor and such an action may be attributed to the reduction in calcium influx in carotid baroreceptor, which is mediated by IR and α 2 AR.[WT5HZ]

关 键 词：胍丁胺 压力感受器活动 窦神经传入放电 咪唑啉受体 α2肾上腺素受体 大鼠 颈动脉窦 

分 类 号：Q463[生物学—生理学]