Taylor A C
J Exp Biol. 1976 Jun;64(3):751-9. doi: 10.1242/jeb.64.3.751.
Shell closure in Arctica islandica is followed by an exponential decrease in the oxygen tension of the mantle cavity water and is accompanied by an initial increase in heart rate which is followed at lower oxygen tensions by a bradycardia. Prior to shell opening there is a slight increase in heart rate before any movement of the shell valves can be detected. However, once the shell opens and pumping activity recommences there is a rapid increase in heart rate, often to levels above normal. Perfusion of the mantle cavity with water of high and low oxygen tension resulted in the cardiac responses normally associated with shell opening and closure. Recordings of the PO2 of the blood in the ventricle, made simultaneously with cardiac recordings, showed that the changes in heart rate were recorded only after the PO2 of the blood had changed. These experiments suggest that changes in the PO2 of the mantle cavity water may be primarily responsible for the cardiac responses to shell closure in Arctica.
在冰岛北极蛤中，贝壳闭合后，外套腔水中的氧张力呈指数下降，同时心率最初会增加，在较低氧张力下则会出现心动过缓。在贝壳打开之前，在检测到贝壳瓣有任何运动之前，心率会略有增加。然而，一旦贝壳打开且泵血活动重新开始，心率就会迅速增加，通常会高于正常水平。用高氧张力和低氧张力的水灌注外套腔会导致出现与贝壳打开和闭合相关的正常心脏反应。与心脏记录同时进行的心室血液PO₂记录表明，只有在血液PO₂发生变化后才记录到心率变化。这些实验表明，外套腔水中PO₂的变化可能是冰岛北极蛤对贝壳闭合产生心脏反应的主要原因。
