Effect of W-7 on ionic fluxes and electrical activity of mouse pancreatic islets.
W-7 (N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide) (0.1 mM), a calmodulin inhibiting compound, suppressed the reincrease of 86Rb+ efflux from pancreatic islets normally seen in response to lowering the glucose concentration from stimulated to basal value. Ionophore (A23187)-induced increase was completely abolished. W-7 inhibited 45Ca2+ uptake and stimulation of 45Ca2+ efflux in response to glucose (11.1 mM) but did not affect K+ (20 mM)-induced 45Ca2+ uptake. Electrical activity of B-cells at 11.1 mM glucose showed a prolongation in burst length in the presence of 0.1 mM W-7. The data suggest that W-7 affects the opening properties of K+ channels resulting in a delayed repolarisation of the cells possibly through its inhibitory action on Ca2(+)-activated calmodulin.
Wahl
M A
MA
Department of Pharmacology, Eberhard-Karls Universität Tübingen, F.R.G.
Spenny
K A
KA
Safayhi
H
H
Ammon
H P
HP
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D004594:Electrophysiology; D005260:Female; D005947:Glucose / Q000494:pharmacology; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D051379:Mice; D011189:Potassium Chloride / Q000494:pharmacology; D012413:Rubidium / Q000378:metabolism*; D012414:Rubidium Radioisotopes; D013449:Sulfonamides / Q000494:pharmacology*
D002132:Calcium Radioisotopes; D002147:Calmodulin; D012414:Rubidium Radioisotopes; D013449:Sulfonamides; D000001:Calcimycin; C017967:W 7; D011189:Potassium Chloride; D005947:Glucose; D012413:Rubidium; D002118:Calcium