Morphological and electrophysiological properties of single myocardial cells from Koch triangle of rabbit heart  

作　　者：REN Fu-xian NIU Xiao-lin OU Yan HAN Zhen-hua LING Feng-dong ZHOU Shi-sheng LI Ya-jie 

机构地区：[1]Department of Cardiology, Second Hospital, Xi＇an Jiaotong University, Xi＇an 710004, China [2]Key Laboratory of Environment and Genes Related to Diseases,Ministry of Education, Xi＇an 710061, China [3]Department of Anatomy, Xi＇an Jiaotong University School of Medicine, Xi＇an 710061, China [4]Institute of Basic Medical Science, Dalian University School of Medicine, Dalian 116622, China （Zhou SS and Li YJ）

出　　处：《Chinese Medical Journal》2006年第24期2075-2084,共10页中华医学杂志（英文版）

基　　金：ThisstudywassupportedbytheNationalNaturalScienceFoundationofChina(No.30070307);theNationalSpecialFundforDoctoralEducation&ResearchProgram,MinistryofEducation,China(No.20030698009)

摘　　要：Background The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate their complex electrophysiological phenomena. Methods Experiments were conducted using cooled charge coupling device （CCD） system and whole cell, patch clamp technique to determine the morphology, action potential and sodium current density of single viable myocytes enzymatically isolated from the Koch triangle of rabbit hearts. Results Morphologically, cardiac cells in shape of spider, tiny spindle, slender spindle, rod and strip were observed in percentage of 3.0±0.3, 35.0±5.0, 15.0±2.0, 40.0±5.0 and 6.0±0.7 respectively. The cellular dimensions and capacitance gradually increased in the above order （all P〈0.05）. Electrophysiologically, action potential configurations recorded from them were similar respectively to nodal （N）, atrial nodal （AN）, nodal Hisian （NH）, atrial （A） and Hisian like potentials obtained from the intact atrioventricular nodal preparations. Diastolic depolarization appeared in all myocytes except for rod cells. Sodium current density increased in the order of tiny spindle, strip, rod, slender spindle cell （all P〈0.05）, but could not be detected in spider-shaped cells. Linear regression analysis revealed that membrane capacitance was correlated negatively to the rate of diastolic depolarization r=-0.70, P〈0.001, but positively to maximum depolarization potential, amplitude of action potential, upstroke velocity and maximum peak value of sodium current density r=0.84, 0.80, 0.87 and 0.75, respectively; all P〈0.001. Conclusions The results demonstrated that spider-shaped, spindle, rod and strip cells in Koch triangle might correspond to pacemaking, transitional, atrial and Purkinje like cells, respectively. Furthermore, tiny spindle and slender spindle cells were referred to transitional cell α （TCα） and β （TCβ） accordingly considBackground The morphological and electrophysiological characteristics of cardiac cells in Koch triangle are still disputed. We studied the appearance and electrical properties of these diverse myocytes to elucidate their complex electrophysiological phenomena. Methods Experiments were conducted using cooled charge coupling device （CCD） system and whole cell, patch clamp technique to determine the morphology, action potential and sodium current density of single viable myocytes enzymatically isolated from the Koch triangle of rabbit hearts. Results Morphologically, cardiac cells in shape of spider, tiny spindle, slender spindle, rod and strip were observed in percentage of 3.0±0.3, 35.0±5.0, 15.0±2.0, 40.0±5.0 and 6.0±0.7 respectively. The cellular dimensions and capacitance gradually increased in the above order （all P〈0.05）. Electrophysiologically, action potential configurations recorded from them were similar respectively to nodal （N）, atrial nodal （AN）, nodal Hisian （NH）, atrial （A） and Hisian like potentials obtained from the intact atrioventricular nodal preparations. Diastolic depolarization appeared in all myocytes except for rod cells. Sodium current density increased in the order of tiny spindle, strip, rod, slender spindle cell （all P〈0.05）, but could not be detected in spider-shaped cells. Linear regression analysis revealed that membrane capacitance was correlated negatively to the rate of diastolic depolarization r=-0.70, P〈0.001, but positively to maximum depolarization potential, amplitude of action potential, upstroke velocity and maximum peak value of sodium current density r=0.84, 0.80, 0.87 and 0.75, respectively; all P〈0.001. Conclusions The results demonstrated that spider-shaped, spindle, rod and strip cells in Koch triangle might correspond to pacemaking, transitional, atrial and Purkinje like cells, respectively. Furthermore, tiny spindle and slender spindle cells were referred to transitional cell α （TCα） and β （TCβ） accordingly consid

关 键 词：triangle of Koch transitional cell action potential sodium current patch clamp 

分 类 号：R331.38[医药卫生—人体生理学] Q463[医药卫生—基础医学]