Yan H Y, Fine M L, Horn N S, Colón W E
Thomas H Morgan School of Biological Sciences, University of Kentucky, Lexington 40506, USA.
J Comp Physiol A. 2000 May;186(5):435-45. doi: 10.1007/s003590050443.
The teleost gasbladder is believed to aid in fish audition by transferring pressure components of incoming sound to the inner ears. This idea is primarily based on both anatomical observations of the mechanical connection between the gasbladder and the ear, followed by physiological experiments by various researchers. The gasbladder movement has been modeled mathematically as a pulsating bubble. This study is extending the previous work on fish with a physical coupling of the gasbladder and ear by investigating hearing in two species (the blue gourami Trichogaster trichopterus, and the oyster toadfish Opsanus tau) without a mechanical linkage. An otophysan specialist (the goldfish Carassius auratus) with mechanical coupling, is used as the control. Audiograms were obtained with acoustically evoked potentials (e.g., auditory brainstem response) from intact fish and from the same individuals with their gasbladders deflated. In blue gourami and oyster toadfish, removal of gas did not significantly change thresholds, and evoked potentials had similar waveforms. In goldfish thresholds increased by 33-55 dB (frequency dependent) after deflation, and major changes in evoked potentials were observed. These results suggest that the gasbladder may not serve an auditory enhancement function in teleost fishes that lack mechanical coupling between the gasbladder and the inner ear.
硬骨鱼的鳔被认为通过将传入声音的压力成分传递到内耳来辅助鱼类听觉。这个观点主要基于对鳔与耳朵之间机械连接的解剖学观察，随后是不同研究人员进行的生理学实验。鳔的运动已被数学建模为一个脉动气泡。本研究通过调查两种没有机械联系的物种（蓝曼龙鱼Trichogaster trichopterus和牡蛎蟾鱼Opsanus tau）的听力，扩展了先前关于鳔与耳朵物理耦合的鱼类研究。一种具有机械耦合的骨鳔鱼类专家（金鱼Carassius auratus）被用作对照。通过对完整鱼类以及鳔被放气后的同一批个体进行声诱发电位（如听觉脑干反应）测量来获得听力图。在蓝曼龙鱼和牡蛎蟾鱼中，去除气体并没有显著改变阈值，并且诱发电位具有相似的波形。在金鱼中，放气后阈值增加了33 - 55分贝（取决于频率），并且观察到诱发电位有重大变化。这些结果表明，在鳔与内耳之间缺乏机械耦合的硬骨鱼类中，鳔可能不具有听觉增强功能。
