Modulation of ion uptake across posterior gills of the crab Chasmagnathus granulatus by dopamine and cAMP.
Comp Biochem Physiol A Mol Integr Physiol
; 139(1): 103-9, 2004 Sep.
Article
de En
| MEDLINE
| ID: mdl-15471687
ABSTRACT
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.
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Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Dopamine
/
AMP cyclique
/
Brachyura
/
Ions
Limites:
Animals
Langue:
En
Journal:
Comp Biochem Physiol A Mol Integr Physiol
Sujet du journal:
BIOLOGIA MOLECULAR
/
FISIOLOGIA
Année:
2004
Type de document:
Article
Pays d'affiliation:
Argentine