食蚊鱼的生物电场特征

THE BIOELECTRIC FIELD OF GAMBUSIA AFFINIS

文章采用活体记录的方法测量了食蚊鱼(Gambusia affinis)的生物电场。实验分单尾鱼、两尾鱼同向和两尾鱼反向三组测量,每组10个重复。结果表明:单尾鱼的生物电场表现为头负、尾正的偶极子直流电场,头部相对电势为(–24±2.4)μV,尾部为(21±1.6)μV,且头部附近产生1—3 Hz与呼吸频率对应的交流呼吸电场,大小为(4.2±0.8)μV。两尾鱼生物电场测量表明,其直流电场均大于单尾鱼(P<0.05);两尾鱼同向靠近时产生的交流呼吸电场显著大于单尾鱼(P<0.01),而反向靠近时产生的呼吸电场显著小于单尾鱼(P<0.001)。这表明两条鱼不同方向靠近时,可通过呼吸作用改变交流呼吸电场的大小。此种现象对于依靠感知交流呼吸电场来摄食的被动电感受鱼类是不利的。

Sturgeon is an ancestor electrosensory fish which is able to sense the electric fields of prey animals and other sources.The character of bioelectric fields in environment is an important stimulus to investigate the electrosensory information processing in the brain.However,there were a few documents on bioelectric fields.In this study,the bio-electric fields of Gambusia affinis were measured in living fish,which was used as prey fish of Siberian Sturgeon in laboratory and the common small fish in southern China.They were measured and charactered in three experimental groups： single fish group,pair in same direction group and pair in opposite direction group.The bioelectric field of sin-gle fish showed typical features of dipole field,with relative potential up to（–24±2.4） μV on head and（21±1.6） μV on tail.There was（4.2±0.8） μV alternating current electric with 1—3 Hz on head which was corresponded with the respi-ratory rhythm of the fish.In other two experimental groups,the direct current electric fields were larger than the single fish group（P0.05）.However,the alternating current electric field of single fish group was significant bigger than pair in opposite direction group（3.8±0.7） μV but smaller than pairs in same direction group（4.5±0.8） μV（P0.01）.It sug-gested that the schooling fish could evade the predators by modulating the alternating current respiratory potential.It was maybe a kind of ancestral anti–predator strategy for fish to meet the passive electroreception,and further research would carry on electrophysiology.