Abstract
When acutely transferred to diluted seawater (SW), Procephalothrix spiralis and Clitellio arenarius regulate water content (g H2O/g solute free dry wt = s.f.d.w.) via loss of Na and Cl (µmoles/g.s.f.d.w.). The present study extends these observations to a greater range of salinities and determines the effects of long-term, stepwise acclimation to diluted seawaters. Final exposure to a given experimental seawater (70, 50, 30, 15%) was 48 hours. Osmolality (mOsm/kg H2O) and Na, K, and Cl ion concentrations (mEq/l) were determined in total tissue water and in the extracellular fluid of C. arenarius. Extracellular volume was determined as the 14C-polyethylene glycol space. Both species behaved as hyperosmotic conformers in diluted seawaters. However, reduction of the osmotic gradient between worm and medium occurred in P. spiralis, but not C. arenarius, in 30 and 15% SW. In both species, osmolality and Na, Cl, and K concentrations in total tissue water decreased with increased dilution of the SW. Water content increased with dilution of the medium but was lower than that which would be predicted based on approximation of the van't Hoff relation. This indicated the occurrence of regulatory volume decrease (RVD). In P. spiralis, in 70 or 50% SW, RVD was accompanied by loss of Na and Cl contents. However, in 30 or 15% SW, Na and Cl contents increased and in worms in 15% SW K content decreased. The latter movements of Na, Cl and K are indicative of cellular hysteresis and were associated with decreased viability, indicating the lower limits of regulatory ability in this species. In comparison, RVD in C. arenarius occurred in all diluted seawaters and was accompanied by loss of Na and Cl contents. In C. arenarius, evidence for reduced viability was absent. Removal of the supra- and subesophageal ganglia of C. arenarius resulted in retention of water, Na and Cl (g H2O or µmoles/g s.f.d.w.) in worms acclimated to 70% SW. Removal of the cerebral ganglia and cephalic glands of P. spiralis did not significantly influence regulation of water content.
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References
Drawert, W., 1968. Histophysiologische Untersuchungen zur Beziehung zwischen Osmoregulation und Sekretionstätigkeit in Nervensystem von Enchytraeus albidus Henle. Zool. Jb. Physiol. 74: 292–318.
Ferraris, J. D., 1979a. Histological study of secretory structures of nemerteans subjected to stress. I. Neurosecretory systems. Gen. comp. Endocrinol. 39: 423–433.
Ferraris, J. D., 1979b. Histological study of secretory structures on nemerteans subjected to stress. II. Cerebral organs. Gen. comp. Endocrinol. 39: 434–450.
Ferraris, J. D., 1979c. Histological study of secretory structures of nemerteans subjected to stress. II. Cerebral organs. Gen. comp. Endocrinol. 39: 451–466.
Ferraris, J. D., 1984. Volume regulation in intertidal Procephalothrix spiralis (Nemertina) and Clitellio arenarius (Oligochaeta) II. Effects of decerebration under fluctuating salinity conditions. J. comp. Physiol. B. 154: 125–137.
Ferraris, J. D., 1985a. Effects of ablation of the cerebral organs and cerebral ganglia on volume regulation in an intertidal nemertine Paranemertes peregrina. Physiol. Zool. 58: 117–128.
Ferraris, J. D., 1985b. Putative neuroendocrine devices in the nemertina — An overview of structure and function. Am. Zool. 25: 73–85.
Ferraris, J. D. & B. Schmidt-Nielsen, 1982a. Volume regulation in an intertidal oligochaete, Clitellio arenarius (Müller). I. Short-term effects and the influence of the supra- and subesophageal ganglia. J. exp. Zool. 222: 113–128.
Ferraris, J. D. & B. Schmidt-Nielsen, 1982b. Volume regulation in an intertidal nemertine, Procephalothrix spiralis Coe. I. Short-term effects and independence of decerebration. J. exp. Zool. 224: 307–319.
Freel, R. W., 1978. Patterns of water and solute regulation in the muscle fibers of osmoconforming marine decapod crustaceans. J. exp. Biol. 72: 107–126.
Freel, R. W., S. G. Medler & M. E. Clark, 1973. Solute adjustments in the coelomic fluid and muscle fibers of a euryhaline polychaete, Neanthes succinia, adapted to various salinities. Biol. Bull. 144: 289–303.
Lasserre, P., 1975. Métabolisme et osmorégulation chez une annélide oligochète de la méiofaune: Marionina achaeta Lasserre. Cah. Biol. mar. 16: 765–798.
Lechenault, H., 1965a. Neurosécrétion et osmorégulation chez les Lineidae (Hétéronémertes). C. r. Acad. Sci., Paris 261: 4868–4871.
Lechenault, H., 1965b. Osmorégulation et neurosécrétion chez les Lineidae (Némertes). Gen. comp. Endocrin. 5: 695.
Oglesby, L. C., 1978. Salt and water balance. In P. J. Mill (ed.), The Physiology of Annelids. Academic Press, New York: 555–658.
Pfannkuche, O., 1980. Distribution and abundance of Tubificidae and Naididae (Oligochaeta) in a brackish-water fjord, with special reference to the α-mesohaline zone. Neth. J. Sea Res. 14: 78–93.
Schmidt-Nielsen, B., B. Graves & J. Roth, 1983. Water removal and solute additions determining increases in renal medullary osmolality. Am. J. Physiol. 244: F472-F482.
Schöne, C., 1971. Über den Einfluss von Nahrung und Substrasalinität auf Verhalten Fortpflanzung und Wasserhaushalt von Enchytraeus albidus Henle (Oligochaeta). Oecologia 6: 254–266.
Varndell, I. M., 1981. Physiological studies on the eulittoral nemerteans Amphiporus lactifloreus and Lineus ruber. Ph.D. thesis, University of Leeds, 507 pp.
Warren, K. M. & S. K. Pierce, 1982. Two cell volume regulatory systems in the Limulus myocardium: an interaction of ions and quarternary ammonium compounds. Biol. Bull. 163: 504–516.
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Ferraris, J.D., Norenburg, J.L. Water and solute regulation in Procephalothrix spiralis Coe and Clitellio arenarius (Müller) III. Long-term acclimation to diluted seawaters and effect of putative neuroendocrine structures. Hydrobiologia 156, 161–173 (1988). https://doi.org/10.1007/BF00027990
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DOI: https://doi.org/10.1007/BF00027990