Calcium control of metamorphosis in polychaete larvae

✍ Scribed by Ilan, Micha ;Jensen, Rebecca A. ;Morse, Daniel E.

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 762 KB
• Volume: 267
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402670408

✦ Synopsis

Abstract

The importance of Ca^2+^ in the control of metamorphosis of a marine invertebrate larva was investigated. An excess of [Ca^2+^] in the external medium induced metamorphosis of Phragmatopoma californica (polychaete) larvae in a concentration‐dependent manner. This effect is specific for calcium, and not simply the result of osmotic changes, as an excess of Mg^2+^ did not induce metamorphosis. Consistent with this finding, the calcium ionophore, A23187, also induced metamorphosis in a concentration‐dependent manner. Paradoxically, however, the aromatic compounds diltiazem, verapamil, D600, and nifedipine, known to block Ca^2+^ channels in other systems, also induced metamorphosis. When exposed to diltiazem for only 20 h and subsequently washed free of this compound, 95% of the larvae metamorphosed and developed normally. Previous studies have demonstrated that the induction of metamorphosis in Phragmatopoma californica is controlled by chemosensory recognition of an exogenous morphogen and mediated by an excitatory pathway that involves adenyl cyclase and cyclic AMP. Because cellular excitation and cyclic AMP‐dependent signal transduction generally involve the participation of calcium ion, the most parsimonious explanation for the results reported here include (1) direct control of the morphogenetic pathway by calcium ion, and (2) complexities of the calcium regulation of this process, or a functional similarity between the structurally related aromatic effectors tested and the natural inducer of metamorphosis. © 1993 wiley‐Liss, Inc.