Effect of glucose on endothelin-1-induced calcium transients in cultured bovine retinal pericytes.
Published work has shown that endothelin-1-induced contractility of bovine retinal pericytes is reduced after culture in high concentrations of glucose. The purpose of the present study was to establish the profile of endothelin-1-induced calcium transients in pericytes and to identify changes occurring after culture in high concentrations of glucose. Glucose had no effect on basal levels of cytosolic calcium or on endothelin-1-induced calcium release from intracellular stores. However, influx of calcium from the extracellular medium after endothelin-1 stimulation was reduced in pericytes that had been cultured in 25 mM D-glucose. L-type Ca(2+) currents were identified by patch clamping. The L-type Ca(2+) channel agonist, (-)-Bay K8644, caused less influx of calcium from the extracellular medium in pericytes that had been cultured in 25 mM D-glucose than in those cultured with 5 mM D-glucose. However, 3-O-methylglucose, a nonmetabolizable analogue of glucose which can cause glycation, had similar effects to those of high concentrations of glucose. The results suggest that reduced function of the L-type Ca(2+) channel that occurs in bovine retinal pericytes after culture in high concentrations of D-glucose is probably due to glycation of a channel protein.
McGinty
A
A
Department of Clinical Biochemistry, Queen's University of Belfast, Belfast BT12 6BA, United Kingdom.
Scholfield
C N
CN
Liu
W H
WH
Anderson
P
P
Hoey
D E
DE
Trimble
E R
ER
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002417:Cattle; D002478:Cells, Cultured; D004347:Drug Interactions; D019332:Endothelin-1 / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects; D018408:Patch-Clamp Techniques; D020286:Pericytes / Q000502:physiology*; D012160:Retina / Q000166:cytology / Q000502:physiology
D019332:Endothelin-1; D005947:Glucose; D002118:Calcium