期刊
JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY
卷 295, 期 2, 页码 157-171出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/S0022-0981(03)00292-2
关键词
cardiac activity; branchial physiology; detoxication; 5-hydroxytryptamine; dopamine; bivalve
Acute, sublethal, copper exposures induced bimodal physiological responses in the mytilid mussel Perna viridis. Whole animal studies revealed that copper increased heart rate (mild tachycardia) whilst clearance rates and hence gill cilia were simultaneously inhibited. The inhibitory bioamine dopamine reversed tachycardia, indicating that elevated heart rates were due to nervous (serotonergic) stimulation of the myocytes. The excitatory bioamine 5-hydroxytryptamine failed to reverse copper-induced inhibition of clearance rates, suggesting that mechanical damage or blockage of the cilia rather than overt neurotoxicity was impairing the function of the gill. The digestive diverticula was the major copper-accumulating organ although rapid metal exocytosis was evident when individuals were allowed to depurate in uncontaminated seawater. Waste products are expelled from the digestive diverticula into the intestine and as the rectum passes through the heart, elevated rates of ventricular contraction may facilitate egestion of metal-rich faeces. Elevated cardiac activity during exposure to copper may serve to increase ventricular pulsatile pressure on the rectum for the expulsion of metal-rich faecal inclusions (coproliths) derived from the digestive diverticula, lysosomes. This study describes a relationship between the heart, alimentary canal and digestive diverticula lysosomes as a pathway for metal detoxication in mytilid mussels. (C) 2003 Elsevier B.V. All rights reserved.
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