Cellular signalling of PCH-induced pigment aggregation in the crustacean Macrobrachium potiuna erythrophores |
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Authors: | Luiz Eduardo Maia Nery Marcelo Alves da Silva Lars Josefsson Ana Maria Lauro Castrucci |
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Institution: | Laboratório de Zoofisiologia, Departamento de Ciências Fisiológicas, Funda??o Universidade do Rio Grande, Rio Grande, RS, 96201-900, Brasil, XX Departamento de Fisiologia, Instituto de Biociências, Universidade de S?o Paulo, Brasil, Tel.: +55-11/7422818-7610; Fax: +55-11/7422818, e-mail: amdlcast@usp.br, XX Department of Biochemistry, University of Copenhagen, Copenhagen, Denmark, DK
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Abstract: | The cellular system responsible for the transduction of the pigment-concentrating hormone (PCH) signal was investigated in
erythrophores of the freshwater shrimp, Macrobrachium potiuna. Dose-response curves to the hormone were determined in the absence and in the presence of several drugs that affect sequential
steps of the Ca2+-dependent signalling pathway. Additionally, the ability of forskolin to induce pigment dispersion was evaluated. Neomycin
sulphate (10−4 and 10−3 mol · l−1), trifluoperazine (10−5 and 10−4 mol · l−1), 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (10−7 and 10−5 mol · l−1) and okadaic acid (10−7 mol · l−1) significantly (P<0.05) decreased the responses to PCH. However, okadaic acid at low concentration (10−9 mol · l−1) and cyclosporin A (10−6 and 10−5 mol · l−1) did not significantly (P>0.05) affect PCH activity. Forskolin (10−4 mol · l−1) was able to half-maximally reverse the hormone-induced aggregation. Our results suggest that the pigment-concentrating hormone
induces pigment aggregation through a Ca2+-dependent pathway with a posteriori phosphatase activation, probably the serine/threonine phosphatase 1.
Accepted: 30 June 1997 |
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Keywords: | Pigment concentrating hormone Erythrophore Calcium signalling Protein kinase C Macrobrachium potiuna |
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