Efeito de monoaminas sobre a contração muscular em crustáceos decápodes / Effect of monoamines on the muscular contraction in decapods crustaceans

Varios neurotransmissores de vertebrados ja foram identificados em invertebrados, porem,suas funcoes fisiologicas ainda nao estao completamente esclarecidas. Em crustaceos, as monoaminasregulam, entre outras funcoes, a muda, a reproducao, a osmorregulacao, o metabolismo decarboidratos, e a contracao muscular, onde tem um papel importante no controle da postura. Opresente trabalho tem por objetivo estudar os efeitos da administracao de monoaminas sobre acontracao muscular no lagostim Parastacus defossus (Faxon, 1898) e no caranguejo Chasmagnathusgranulata (Dana, 1851). Os caranguejos foram coletados em Imbe e os lagostins foram coletados naregiao do Lami, no Municipio de Porto Alegre/RS. Em ambos animais, a administracao de serotoninacausou uma alteracao postural caracterizada por grande rigidez muscular em flexao enquanto adopamina causou hipertonia da musculatura extensora. Estes resultados estao de acordo com osdescritos em outras especies de crustaceos decapodes. Almost all vertebrate neurotransmitters have already been identified in invertebrates, but theirfunctions in these animals are still not completely understood. In crustaceans, it seems that monoaminesare involved in the regulation of ecdise, reproduction, carbohydrate metabolism, osmoregulation,muscular contraction and posture. The objective of this work was to study the effects of serotonine anddopamine administration on the muscular contraction in the crayfish Parastacus defossus (Faxon,1898) and in the crab Chasmagnathus granulata (Dana, 1851). The crabs were collected in TramandaiLagoon, (Imbe, Brazil) and the crayfish were collected in swamps around the city of Porto Alegre(Brazil). In both animals, the administration of serotonine caused the contraction of the flexor musculature,while dopamine administration caused the contraction of extensor musculature. Both monoaminesseverely altered the posture of the animals. These findings are in agreement with previous descriptionsof monoamines administration in other crustacean species.