Effect of atriopeptin II on isolated opercular epithelium of Fundulus heteroclitus.
The effect of atriopeptin II (ANF) on the in vitro opercular epithelium was investigated by use of short-circuit current techniques. Serosal addition of ANF stimulates chloride secretion (short-circuit current) 19% above control values with a 7% increase in tissue conductance. Mucosal addition of ANF to the opercular epithelium was without effect. The ANF stimulation of the current was dose dependent with a maximum at 10(-7) M. The addition of ANF had no effect on the current or the conductance of opercular epithelia bathed in Cl--free Ringer. The opercular current could be stimulated above the ANF response by isoproterenol (10(-6) M). Pretreatment of the opercular epithelium with propranolol (10(-5) M) did not inhibit the stimulation of the short-circuit current by ANF but did inhibit the isoproterenol response indicating that the ANF stimulatory activity was independent of the beta-adrenergic receptors. The ANF-stimulated short-circuit current was found in operculi pretreated with tetrodotoxin (10(-6) or 10(-5) M) or diltiazem (10(-4) M) indicating the ANF response was not due to nerve stimulation. Pretreatment of opercular tissue with dibutyryl adenosine 3',5'-cyclic monophosphate, 8-bromoadenosine 3',5'-cyclic monophosphate, or 8-bromoguanosine 3',5'-cyclic monophosphate (10(-4) M) had no effect on the ANF stimulatory response. Opercular epithelia from short-term freshwater-adapted killifish also showed the ANF-induced response. The stimulation of chloride secretion in Fundulus heteroclitus chloride cells by ANF may have a role in teleost ion regulation.
Scheide
J I
JI
Mount Desert Island Biological Laboratory, Salsbury Cove, Maine 04672.
Zadunaisky
J A
JA
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001692:Biological Transport; D003994:Bucladesine / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology; D004594:Electrophysiology; D004848:Epithelium / Q000187:drug effects; D005260:Female; D005399:Fishes; D005880:Gills / Q000166:cytology / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology
D002712:Chlorides; D011943:Receptors, Adrenergic, beta; D003995:Dibutyryl Cyclic GMP; D013779:Tetrodotoxin; D003994:Bucladesine; D009320:Atrial Natriuretic Factor; D007545:Isoproterenol