成年蟾蜍神经－肌接头小终板电位的季节性变化与年节律

Seasonal Variation and Circannual Rhythm of Miniature End Plate Potentials Recorded from the Neuromuscular Junctions of the Adult Toad ( Bufo Bufo Gargarizans )

用微电极细胞内记录小终板电位（ＭＥＰＰ）的电生理学技术，在６６只雌性、６２只雄性成年蟾蜍缝匠肌神经－肌接头研究了ＭＥＰＰ的季节性变化与年节律。结果：①１年里ＭＥＰＰ的逐月平均振幅呈现明显的季节性变化，在春季的３、４月最高，而在秋季的９、１０月最低；②单余弦法分析和零振幅检验证明，此季节性变化呈近年节律性波动（Ｐ＜０．００１），其调整中值、振幅和峰值时相３个参数在雌性分别为０．２９±０．０５ｍＶ、０．２５ｍＶ和－９７．１７°，在雄性分别为０．１９±０．０２ｍＶ、０．１６ｍＶ和－９２．０１°。雌性的年节律较雄性的更明显（Ｐ＜０．０５）；③无论雌、雄蟾蜍ＭＥＰＰ的频率波动在统计学上既无明显的季节性改变，也无年节律。

The seasonal variations and circannual rhythm of miniature end plate potentials (MEPP) recorded from the sartorius neuromuscular junctions (NMJ) of 66 female and 62 male adult toads ( Bufo bufo gargarizans ) were studied with intracellular microelectrode recording techniques of electrophysiology.The results revealed that the mean amplitude of MEPP in each month of a year showed clear seasonal variation with a nadir in September and October and a zenith in March and April.This seasonal variation in MEPP amplitude was proved to be a circannual rhythm by single cosinor analysis and zero amplitude test,and the three parameters of the rhythm,i.e.mesor,amplitude and acrophase were 0.29±0.05mV,0.25mV and -97.17° in female toad and 0.19± 0.02mV, 0.16 mV and -92.01° in male toad,respectively;the circannual rhythm in female toad was more distinct than that in male.Neither seasonal variation nor circannual rhythm was statistically significant in the changes of frequency of MEPP,regardless of toad sexuality.