SHIFTS IN FREQUENCY TUNING OF ELECTRORECEPTORS IN ANDROGEN-TREATED MORMYRID FISH
SHIFTS IN FREQUENCY TUNING OF ELECTRORECEPTORS IN ANDROGEN-TREATED MORMYRID FISH
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DOI：
10.1007/bf00611588
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发表时间：
1984-01-01
期刊：
影响因子：
--
通讯作者：
HOPKINS, CD
中科院分区：
文献类型：
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作者：
BASS, AH;HOPKINS, CD
几种电鱼在电器官放电（EOD）的脉冲波形上存在性别差异。在西非加蓬进行的实地研究表明，对于其中一种物种，即短尾布氏蝇（三期），性成熟的雄性排爆期在形状上有所不同，其持续时间几乎是雌性和幼虫排爆期的两倍。傅里叶分析表明，排爆持续时间的差异与排爆功率谱的差异相关，排爆功率谱的峰值在雄性的0.3 kHz，雌性和幼鱼的1.3 kHz。研究发现，至少有一类电感受器（称为Knollenorgans）的频率调谐存在相应的性别差异。与雌性和幼鱼相比，雄性的knolenorgans平均最佳或特征频率较低。这与男性脉冲功率谱中的低峰值有关。当雌性接受性腺雄激素治疗时，其eod持续时间增加2-3倍，其脉冲功率谱相应降低，与成熟雄性相匹配。knollenorgan的平均最佳频率降低了近1khz，这与它们的EOD功率谱向下移动相匹配。对于从尼日利亚商业进口的第二种布氏蝇（sp. 2），在爆炸处理的功率谱或持续时间中发现了性别差异。功率谱峰值在。约。雄性、雌性和青少年的频率为4.2 kHz。雄激素确实会导致EOD功率谱的平均峰值（从4.2-1.3 kHz）和Knollenorgans的平均最佳频率（从2.3-1.4 kHz）同时向下移动。通过外科手术手段电沉默的Brienomyrus （sp. 2）标本平均只比对照动物高0.2 kHz。接受雄激素治疗的沉默动物的声音平均比对照组低0.2千赫。如果电感受器没有受到外部电刺激（即动物自身的EOD）的刺激，那么在雄激素治疗期间，电感受器的调节可能只能部分地改变。由于雄激素处理仅在完整的鱼中对受体调节有显著影响，因此似乎恢复可能不是由于雄激素对受体的直接作用，而是由于主要电刺激对受体的作用，即EOD。讨论了这些结果对电感受器调谐的物种发育和性别差异的影响。
Several species of mormyrid electric fish have a sex difference in the pulse waveform of their electric organ discharge (EOD). Field studies in Gabon, West Africa have shown for one such species, Brienomyrus brachyistius (triphasic), that the sexually mature male EOD differs in shape and is nearly twice the duration of the EODs of females and juveniles. Fourier analysis reveals that differences in EOD duration correlate with those in the EOD power spectrum which has a peak at 0.3 kHz in males and 1.3 kHz in females and juveniles. A corresponding sex difference in the frequency tuning of at least 1 class of electroreceptors known as Knollenorgans was found. The average best or characteristic frequency of Knollenorgans is lower in males compared to females and juveniles. This correlates with a lower peak in the power spectrum of the male''s pulse. When females are treated with gonadal androgens, their EODs increase 2-3 fold in duration, and the power spectra of their pulses are correspondingly lowered to match that of mature males. The average best frequency of Knollenorgans decreases by nearly 1 kHz which matches the downward shift of their EOD''s power spectrum. For a 2nd species of Brienomyrus (sp. 2) which is commercially imported from Nigeria, sex difference was detected in the power spectrum or duration of the EOD. The power spectrum peaks at .apprx. 4.2 kHz in males, females and juveniles. Androgens do cauuse a coincident downward shift in the averge peak of the EOD power spectrum (from 4.2-1.3 kHz) and the average best frequency of Knollenorgans (from 2.3-1.4 kHz). Specimens of Brienomyrus (sp. 2) that were electrically silenced by surgical means are tuned, on the average, only 0.2 kHz higher than control animals. Silenced animals that were treated with androgens are tuned, on the average, 0.2 kHz below controls. Electroreceptor tuning probably is only partially modifiable during androgen treatment if the electroreceptors are not being stimulated by an external electrical stimulus, i.e. the animal''s own EOD. Since androgen treatment has a dramatic effect on receptor tuning only in intact fish, it seems likely that retuning is not due to a direct action of androgens on receptors, but rather due to the action of the principal electrical stimulus upon the receptors, i.e., the EOD. The implications of such results for the development of species and sex differences in electroreceptor tuning is discussed.