Dopamine binding directly up-regulates (Na+, K+)-ATPase activity in the gills of the freshwater shrimp Macrobrachium amazonicum

Autor(es)

Lucena, Malson N. ^{[1, 2]} ; Garcon, Daniela P. ^[3] ; Fontes, Carlos F. L. ^[4] ; Fabri, Leonardo M. ^[2] ; Moraes, Cintya M. ^[2] ; McNamara, John C. ^{[5, 6]} ; Leone, Francisco A. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Mato Grosso do Sul, Inst Biociencias, BR-79070900 Campo Grande, MS - Brazil

^[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ave Bandeirantes 3900, BR-14040901 Sao Paulo, SP - Brazil

^[3] Univ Fed Triangulo Mineiro, Campus Univ Iturama, BR-38280000 Uberaba, MG - Brazil

^[4] Univ Fed Rio de Janeiro, Inst Bioquim Med, BR-21941590 Rio De Janeiro, RJ - Brazil

^[5] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, BR-14040901 Sao Paulo, SP - Brazil

^[6] Univ Sao Paulo, Ctr Biol Marinha, Sao Sebastido, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY; v. 233, p. 39-47, JUL 2019.
• Citações Web of Science: 0

Resumo

We examined the effects of exogenous dopamine on gill (Na+, K+)-ATPase activity in vitro in microsomal preparations from juvenile or adult freshwater shrimp, Macrobrachium amazonicum. Dopamine had no effect on enzyme activity in juveniles but stimulated activity in adult shrimp gills by approximate to 35%. Stimulation of the gill (Na+, K+)-ATPase in adult shrimps by 100 mmol L-1 dopamine was characterized kinetically by varying ATP, MgATP, and Na+ and K+ concentrations, together with inhibition by ouabain. Dopamine stimulated ATP hydrolysis by approximate to 40% obeying Michaelis-Menten kinetics, reaching V-M = 190.5 +/- 15.7 nmol Pi min(-1) mg(-1) protein, K-M remaining unaltered. Stimulation by Na+ (approximate to 50%) and K+ (approximate to 25%) revealed distinct kinetic profiles: although K-M values were similar, Na(+)stimulation followed cooperative kinetics, contrasting with the Michaelian kinetics seen for K+. Stimulation by MgATP increased activity by approximate to 30% with little change in K-M. Similar saturation profiles were seen for ouabain inhibition with very similar calculated K-I values. Our findings suggest that dopamine may be involved in hemolymph sodium homeostasis by directly binding to the gill (Na+, K+)-ATPase at a site different from ouabain, thus stimulating enzyme activity in an ontogenetic stage-specific manner. However, dopamine binding does not affect enzyme affinity for cations and ouabain. This is the first report of the direct action of dopamine in stimulating the crustacean gill (Na+, K+)-ATPase. (AU)

• Processo FAPESP: 16/25336-0 - Estudo bioquímico comparativo da (Na+, K+)-ATPase branquial de Macrobrachium amazonicum (Heller, 1862) habitantes de regiões costeiras e continentais
• Beneficiário: Francisco de Assis Leone
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 13/24252-9 - O papel da (Na+,K+)-ATPase na capacidade osmorregulatória do caranguejo Ucides cordatus: uma abordagem bioquímica e molecular
• Beneficiário: Malson Neilson de Lucena
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado