Decreased Basal Cardiac Interstitial Norepinephrine Release after Neuronal Uptake Inhibition in Dogs
Decreased Basal Cardiac Interstitial Norepinephrine Release after Neuronal Uptake Inhibition in Dogs
复制标题
犬神经元摄取抑制后基础心间质去甲肾上腺素释放减少
作者：
D. Cousineau;C. Goresky;C. Rose
本文用多示踪剂稀释-体积平衡法研究了神经元摄取抑制对犬心脏基础间质释放去甲肾上腺素的影响。动力学模型考虑了流量、去甲肾上腺素的毛细血管通透性-表面积、神经递质的间质摄取速率常数和血浆去甲肾上腺素输入和输出值用于估计去甲肾上腺素从间质空间的摄取和释放到间质空间的速率。在基础条件下的麻醉狗中，心脏中示踪剂去甲肾上腺素的间质摄取减少，而主动脉和冠状窦中去甲肾上腺素的血浆浓度没有显著变化。面对这种胺的摄取降低，表明心脏交感神经纤维释放去甲肾上腺素减少。用去甲肾上腺素示踪剂动力学-体积模型分析数据表明，在地昔帕明后，去甲肾上腺素的间质释放减少到与摄取减少相同的程度。结果，心脏细胞外间隙中去甲肾上腺素的浓度没有显著增加。研究结果表明，存在突触前神经元反馈释放抑制，其用于微调基础状态下心肌间质中去甲肾上腺素的浓度，因此，在地昔帕明后，去甲肾上腺素的摄取和释放都相应地减少。
The effect of neuronal uptake inhibition on basal interstitial release of norepinephrine in the canine heart was examined by use of the multiple tracer dilution-bulk balance technique A kinetic model incorporating the effects of flow, capillary permeability-surface product for norepinephrine, the interstitial uptake rate constant for neurotransmitter, and plasma norepinephrine input and output values was used to estimate rates of uptake from and release of norepinephrine into the interstitial space The intravenous injection of the neuronal uptake inhibitor desipramine in anesthetized dogs under basal conditions reduced interstitial uptake of tracer norepinephrine in the heart, without significant changes in plasma concentration of norepinephrine in aorta and coronary sinus The lack of change in the artenovenous balance for norepinephrine across the heart, in the face of the lowered uptake for this amine, suggested that the liberation of norepinephrine by cardiac sympathetic fibers was reduced Analysis of the data with the norepinephrine tracer kinetic-bulk model showed that, after desipramine, the interstitial release of norepinephrine was reduced to the same extent as uptake was diminished. As a result, the concentration of norepinephrine in the extracellular space of the heart did not increase significantly The findings indicate the presence of a presynaptic neuronal feedback inhibition of release, which serves to fine tune the myocardial interstitial concentration of norepinephrine in the basal state, with this, after desipramine, both norepinephrine uptake and release are correspondingly diminished