Silva Ana, Perrone Rossana, Macadar Omar
Depto. de Neurofisiología, Instituto de Investigaciones Biológicas Clemente Estable, Unidad Asociada de Facultad de Ciencias, Universidad de la República, Avda Italia 3318, 11600 Montevideo, Uruguay.
Physiol Behav. 2007 Feb 28;90(2-3):525-36. doi: 10.1016/j.physbeh.2006.11.003. Epub 2006 Dec 18.
The electric organ discharge (EOD) of weakly electric fish encodes information about species, sex, behavioral, and physiological states throughout the lifetime. Its central command is crucial for sensory-motor coordination, and is therefore the target of plastic mechanisms that adapt fish to environmental and social challenges. The EOD waveform of Brachyhypopomus pinnicaudatus is modulated by environmental factors and the neuroendocrine system. In this study we investigate the effects of water temperature and day-night cycle upon EOD rate in this species during the breeding and non-breeding seasons. During the non-breeding season, EOD rate is a linear function of water temperature and exhibits counterclockwise hysteresis. During breeding, a thermal resistance strategy prevents the decrease of EOD rate to cooling. A nocturnal increase of EOD basal rate independent of water temperature and locomotor activity was demonstrated in isolated non-breeding adults and in male-female dyads all year round. An additional increase of nocturnal EOD rate, probably acting as a social courtship signal, was found in breeding dyads. This additional increase of nocturnal EOD rate could not be fully explained by gonadal maturation and was modulated by social stimuli. This study provides novel data on the complex interactions between environment, reproductive cycle, social behavior, and electromotor output in an advantageous model of the vertebrate central nervous system.
弱电鱼的电器官放电（EOD）在其整个生命周期中编码有关物种、性别、行为和生理状态的信息。其核心指令对于感觉运动协调至关重要，因此是使鱼类适应环境和社会挑战的可塑性机制的目标。短尾拟低臀电鳗的EOD波形受环境因素和神经内分泌系统的调节。在本研究中，我们调查了水温与昼夜循环对该物种在繁殖和非繁殖季节EOD频率的影响。在非繁殖季节，EOD频率是水温的线性函数，并呈现逆时针滞后现象。在繁殖期间，一种热抵抗策略可防止EOD频率因降温而降低。全年在隔离的非繁殖成年个体以及雌雄配对个体中均证实，EOD基础频率在夜间会升高，且与水温及运动活动无关。在繁殖配对个体中发现，夜间EOD频率会进一步升高，这可能充当一种社会求偶信号。夜间EOD频率的这种进一步升高无法完全由性腺成熟来解释，且受社会刺激的调节。本研究在脊椎动物中枢神经系统的一个优势模型中，提供了关于环境、生殖周期、社会行为和电运动输出之间复杂相互作用的新数据。
