Detection of salinity by the lobster, Homarus americanus
Detection of salinity by the lobster, Homarus americanus
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DOI：
10.2307/1543620
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发表时间：
2001-12-01
影响因子：
1.6
通讯作者：
Watson, WH
中科院分区：
文献类型：
--
作者：
Dufort, CG;Jury, SH;Watson, WH
龙虾（Homarus americanus）心率的变化被用作动物能够感知周围海水盐度降低的指标。对盐度逐渐降低（1 - 2 ppt/min）的典型反应包括在平均阈值为26.6 +/-0.7ppt时心率迅速增加，随后在盐度达到22.1 +/-0.5ppt时心率降低。心脏反应引起龙虾暴露于等渗无氯盐水，但不等渗钠，镁或钙的盐水。当发生心动过缓时，龙虾的血液渗透压几乎没有变化，这表明所涉及的受体是外部的。此外，没有触角，触角，或腿的龙虾表现出典型的心脏反应，低盐度，表明受体不位于这些地区。暴露于环境海水盐度降低的龙虾，同时两个鳃腔灌注全强度海水，直到外部盐度达到21.6 +/- 1.8 ppt才显示心脏反应。相反，当它们的鳃腔暴露于盐度降低而外部盐度维持在正常水平时，心率的变化迅速引起对非常小的盐度降低的反应（鳃腔降低到29.5 +/- 0.9 ppt，外部降低到31.5 +/- 0.3 ppt）。我们的结论是，主要的受体负责检测降低盐度在H。美洲鳄位于鳃室内或鳃室附近，主要对氯离子敏感。
Changes in the heart rates of lobsters (Homarus americanus) were used as an indicator that the animals were capable of sensing a reduction in the salinity of the ambient seawater. The typical response to a gradual (1 to 2 ppt/min) reduction in salinity consisted of a rapid increase in heart rate at a mean threshold of 26.6 +/- 0.7 ppt, followed by a reduction in heart rate when the salinity reached 22.1 +/- 0.5 ppt, Animals with lesioned cardioregulatory nerves did not exhibit a cardiac response to changes in salinity. A cardiac response was elicited from lobsters exposed to isotonic chloride-free salines but not to isotonic sodium-, magnesium- or calcium-free salines. There was little change in the blood osmolarity of lobsters when bradycardia occurred, suggesting that the receptors involved are external. Furthermore, lobsters without antennae, antennules, or legs showed typical cardiac responses to low salinity, indicating the receptors are not located in these areas. Lobsters exposed to reductions in the salinity of the ambient seawater while both branchial chambers were perfused with full-strength seawater did not display a cardiac response until the external salinity reached 21.6 +/- 1.8 ppt. In contrast, when their branchial chambers were exposed to reductions in salinity while the external salinity was maintained at normal levels, changes in heart rate were rapidly elicited in response to very small reductions in salinity (down to 29.5 +/- 0.9 ppt in the branchial chamber and 31.5 +/- 0.3 ppt externally). We conclude that the primary receptors responsible for detecting reductions in salinity in H. americanus are located within or near the branchial chambers and are primarily sensitive to chloride ions.