L-type calcium channel Ryanodine receptor Nacl Wash out The underlying mechanisms… Plasma membrane myofibrils Membrane depolarization muscle contraction Longitudinal tubule (纵管/肌浆网) Transverse tubule (横管) • To investigate regulatห้องสมุดไป่ตู้on of the frog heart contraction by different factors. 1. Na+,K+, and Ca2+ ; 2. Acetylcholine (Ach) and Norepinephrine (NE) Procedures A classic and the most popular experiment in our school Ringer's solution Transducer Canula Frog heart BL-420 System Objectives • To learn how to intubate and perfuse the frog heart; Dorsal view 注意:在主动脉下面穿2根细线备用 Procedures 4. Ventricle intubation ventricle aorta sinistra arterial cone canula 关键步骤:将蛙心套管的尖端从主动脉插入动脉圆锥 插入心室内的标准:套管内液面随心脏跳动而上下移动 Procedures 5. Connect the frog heart to the transducer; vena cava clip sinus venosus atrium ventricle Dorsal view 注意:1. 切勿损伤静脉窦 2. 张力换能器稍向下倾斜 Procedures 6. Record the contraction of frog heart using BL420 system; Procedures 3. Exposure the frog heart and observe its structure; ventricle arterial cone atrium Aorta sinistra vena cava sinus venosus atrium ventricle Ventral view Observation items • Replace Ringer's solution with 0.65% NaCl; • Add 1-2 drops of CaCl2 (3%) into the canula; • Add 1-2 drops of KCl (2%) into the canula ; • Add 1-2 drops of NE (norepinephrine,1:10000) 1. Sacrifice the frog by destroying its brain and spine; foramen magnum(枕骨大孔) Posterior auricular glands ( 耳后腺) 注意:“麻醉”成功的标准:蛙的四肢松软无力 Procedures 2. Hold the frog to an operating table in a dorsal position; into the canula ; • Add 1-2 drops of Ach (acetylcholine,1:10000) into the canula; 注意:每个项目后都需用新鲜任氏液冲洗套管, 待蛙心活动稳定后再进行下一项 The underlying mechanisms… • How and why do different chemicals change the contraction of frog heart?