Eckhardt E, Pierrot C, Thuet P, Van Herp F, Charmantier-Daures M, Trilles J P, Charmantier G
Department of Animal Physiology, Faculty of Sciences, University of Nijmegen, The Netherlands.
Gen Comp Endocrinol. 1995 Aug;99(2):169-77. doi: 10.1006/gcen.1995.1098.
Isolated posterior gills of the hyper-hyporegulating crab Pachygrapsus marmoratus were perfused with extracts of homologous sinus glands. Sinus gland extracts stimulated the influx of Na+ ions and increased the transepithelial potential difference in the gills in a dose-dependent and reversible fashion. The bioactivity of extracts prepared from crabs that had been acclimated to 10/1000 salinity for at least 1 week was not significantly different from that of extracts prepared from seawater (36/1000 salinity) crabs. The perfusion experiments with both extracts containing two sinus glands significantly increased Na+ influx by about 150% and transepithelial potential difference by about 45%. Sinus gland extracts also increased the Na+/K(+)-ATPase activity by 54% in incubated posterior gills. The bioactivity of extracts was reduced by pronase and trypsin, but not by heating for 10 min at 100 degrees. The molecular weight of the responsible factor(s) was > 5000 Da. Thus, the sinus gland of P. marmoratus is concluded to be involved in the neuroendocrine control of osmoregulation and to contain a peptide(s) that directly influences brachial function.
