title: Serotonin effects in the crab Neohelice granulata: Possible involvement of two types of receptors in peripheral tissues.
abstract: In crustaceans, serotonin (5-HT) controls various physiological processes, such as hormonal secretion, color changes, reproduction, and metabolism. Since 5-HT injections cause hyperglycemia, this study was designed to further investigate this action of 5-HT in the crab Neohelice granulate, fed with a high-carbohydrate (HC) or a high-protein (HP) diet. The effects of pre-treatment with mammalian 5-HT receptor antagonists, cyproheptadine and methiothepin, were also investigated. A series of in vivo experiments with (3)H-5-HT was carried out in order to investigate the presence of putative receptors in peripheral tissues. Since gills were the tissue with the highest labeling in in vivo experiments, in vitro studies with isolated anterior and posterior gills were also conducted. Cyproheptadine blocked the hyperglycemic effect of 5-HT in HP-fed crabs. Methiothepin reduced glycogen levels in the anterior gills of HP crabs and partially blocked the 5-HT-like posture. The injection of (3)H-5-HT identified specific binding sites in all the tissues studied and revealed that the binding can be influenced by the type of diet administered to the crabs. Incubation of the anterior and posterior gills with (3)H-5-HT and 5-HT confirmed the specificity of the binding sites. Both antagonists inhibited (3)H-5-HT binding. In conclusion, this study highlights the importance of serotonin in the control of glucose homeostasis in crustaceans and provides evidences of at least two types of 5-HT binding sites in peripheral tissues. Further studies are necessary to identify the structure of these receptors and their signaling pathways.
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil.
authors: Elen Thegla Sander
authors: ET
authors: Inohara
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil.
authors: Charles Budazewsky
authors: CB
authors: Pinto
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil.
authors: Jorge Felipe Argenta
authors: JF
authors: Model
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil.
authors: Márcia
authors: M
authors: Trapp
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil.
authors: Luiz Carlos
authors: LC
authors: Kucharski
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil.
authors: Roselis Silveira Martins
authors: RS
authors: Da Silva
authors: Laboratório de Metabolismo e Endocrinologia Comparada, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil; Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, Porto Alegre, RS, CEP 90050-170, Brazil. Electronic address: anapaula.vinagre@ufrgs.br.
authors: Anapaula Sommer
authors: AS
authors: Vinagre
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000502:physiology*; D003386:Brachyura / Q000187:drug effects / Q000378:metabolism*; D003533:Cyproheptadine / Q000494:pharmacology; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008719:Methiothepin / Q000494:pharmacology; D009928:Organ Specificity; D011187:Posture; D011985:Receptors, Serotonin / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology
chemical_list: D060829:Arthropod Proteins; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D003533:Cyproheptadine; D012701:Serotonin; D008719:Methiothepin
keywords: Crustacean 5-HT-like receptors; Crustacean hyperglycemic hormone; Diets; Hyperglycemia; Neohelice granulata; Serotonin