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目的 研究电刺激等长收缩运动 (IE)时的中枢内啡肽 (EOPs)对心血管反应的调控机制。方法 成年健康杂种犬 2 0只 ,体质量 ( 11± 1.8)kg ,浅麻醉下以感应电刺激腓肠肌产生最大IE ,包括单侧IE(UIE)和双侧IE(DIE)。测定心率、血压、肺毛细血管楔嵌压、肺动脉压、中心静脉压、心输出量、每搏输出量。采用放射免疫法同批测定血浆及脑脊液中亮氨酸脑啡肽 (LEK )、β 内啡肽 ( β END)、强啡肽 (DYN)含量。结果 ①UIE与DIE时心率、血压、心输出量、血浆及脑脊液LEK、β END、DYN均明显增加 ( P <0 .0 1) ,每搏输出量明显下降 (P <0 .0 1) ;②UIE与DIE相比各血流动力学指标以及血浆LEK、β END、DYN净增量差异无显著性 (P >0 .0 5 ) ;③DIE时脑脊液LEK ,β END ,DYN净增量显著高于UIE( P <0 .0 1)。结论 中枢EOPs对等长收缩运动时心血管反应的调控起重要作用。
Objective To investigate the regulatory mechanism of central endorphins (EOPs) on cardiovascular responses during isometric contraction (IE). Methods Twenty adult healthy hybrid dogs with body weight (11 ± 1.8) kg were anesthetized with light anesthesia to induce maximum gastrocnemius, including unilateral IE (IE) and bilateral IE (DIE). Heart rate, blood pressure, pulmonary capillary wedge pressure, pulmonary artery pressure, central venous pressure, cardiac output, stroke volume were measured. Radioimmunoassay was used to determine the content of LEK, β END and dynorphin in plasma and cerebrospinal fluid. Results ① The heart rate, blood pressure, cardiac output, LEK, β END and DYN in plasma and cerebrospinal fluid of UIE and DIE were significantly increased (P <0.01) and the stroke volume was significantly decreased (P <0.01) Compared with DIE, hemodynamics and plasma LEK, β END, DYN net increment was no significant difference (P> 0.05); ③ DIE cerebrospinal fluid LEK, β END, DYN net increment was significantly higher than the UIE (P <0. 01). Conclusion Central EOPs play an important role in the regulation of cardiovascular response during isometric contraction.