title: [Seasonal variation and circannual rhythm of miniature end-plate potentials recorded from the neuromuscular junctions of the adult toad (Bufo bufo gargarizans)].
abstract: 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 +/- 0.05 mV, 0.25 mV and -97.17 degrees in female toad and 0.19 +/- 0.02 mV, 0.16 mV and -92.01 degrees 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.
authors.affiliation: Research Unit of Neurophysiology, Department of Physiology, Chengdu.
authors.forename: G
authors.initials: G
authors.lastname: Lü
authors.forename: H
authors.initials: H
authors.lastname: Jing
authors.forename: S
authors.initials: S
authors.lastname: Yang
mesh_terms: D000818:Animals; D002023:Bufo bufo; D002940:Circadian Rhythm; D005071:Evoked Potentials; D005260:Female; D008297:Male; D009045:Motor Endplate / Q000502:physiology*; D009469:Neuromuscular Junction / Q000502:physiology*; D010507:Periodicity; D012621:Seasons