INVESTIGADORES
HALPERIN Julia
artículos
Título:
Modulation of ion uptake across posterior gills of the crab Chasmagnathus granulatus by dopamine and cAMP
Autor/es:
HALPERIN J, GENOVESE G, TRESGUERRES M, LUQUET CM
Revista:
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY
Editorial:
ELSEVIER SCIENCE INC
Referencias:
Año: 2004 vol. 139 p. 103 - 109
ISSN:
1095-6433
Resumen:
Cyclic AMP (cAMP) and dopamine modulate ion uptake across isolated and
perfused posterior gills of Chasmagnathus granulatus acclimated to 10
per thousand salinity. Addition of cAMP agonists, such as cp-cAMP,
forskolin, and IBMX, produced a significant increase in the
transepithelial potential difference (Vte), which reflects ion
transport activity. Dopamine (DA) also had a stimulatory effect on ion
uptake, increasing Vte and Na(+) influx, although this effect was
transient, since both variables remained elevated for less than 30 min.
In addition, the dose-response curve for DA concentration-Vte was
biphasic, and the maximum stimulation was obtained with 10 micromol
l(-1). When the effects of forskolin and DA on the Na(+)/K(+)-ATPase
activity were tested, they correlated well with the Vte and Na(+)
influx experiments; the enzyme activity increased significantly after
preincubation of gill fragments for 10 min with forskolin or DA (51 and
64%, respectively), but there was no effect after pre-incubation with
DA for 20 min. Finally, KT5720, a specific inhibitor of cAMP-dependent
protein kinase (PKA), completely abolished the stimulatory effect of DA
on Vte, suggesting the involvement of PKA in this mechanism.