Atriopeptin stimulates chloride secretion in cultured shark rectal gland cells.
Monolayer cultures of shark rectal gland (SRG) epithelial cells were treated with atriopeptin (AP), and the effects on Cl- secretion and intracellular guanosine 3',5'-cyclic monophosphate (cGMP) accumulation were examined. Basolateral or apical exposure to 10(-7) M AP markedly stimulated (8-fold) Cl(-)-dependent, bumetanide-sensitive, short-circuit current (Isc). The AP-stimulated Isc exhibited transient oscillations before reaching a steady state. This behavior is not observed when Isc is activated by other secretagogues such as vasoactive intestinal peptide, 2-chloroadenosine, forskolin, or ionomycin. Intracellular cGMP was concomitantly elevated (10-fold) by 10(-7) M AP. Both Isc stimulation and cGMP accumulation responses exhibited a similar dose dependency beginning at an AP concentration of 1 nM. The bilateral response to AP suggests the presence of receptors on both apical and basolateral plasma membranes. These results are the first demonstration of a direct effect of AP on Cl(-)-secreting epithelial cells. These data also suggest a role for cGMP in mediating Cl- secretion in these cells.
Karnaky
K J
KJ
Department of Anatomy, Medical University of South Carolina, Charleston 29425.
Valentich
J D
JD
Currie
M G
MG
Oehlenschlager
W F
WF
Kennedy
M P
MP
D015762:2-Chloroadenosine / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002034:Bumetanide / Q000494:pharmacology; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology; D004284:Dogfish; D004553:Electric Conductivity; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005260:Female; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D012007:Rectum; D012491:Salt Gland / Q000187:drug effects / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D002712:Chlorides; D002034:Bumetanide; D015762:2-Chloroadenosine; D005576:Colforsin; C016276:8-bromocyclic GMP; D014660:Vasoactive Intestinal Peptide; D015759:Ionomycin; D009320:Atrial Natriuretic Factor; D006152:Cyclic GMP