Effect of intracellular delivery of energy metabolites on intracellular Ca2+ in mouse islets of Langerhans.
Regulation of glucose-induced oscillations in intracellular Ca2+ concentration ([Ca2+]i) was investigated by using a novel technique, electroporation from an electrolyte-filled capillary, to deliver energy metabolites to the intracellular compartment of mouse islets. Intracellular application of ATP resulted in a nifedipine-sensitive increase in [Ca2+]i, consistent with a KATP-channel dependent mechanism of Ca2+ influx. [Ca2+]i in islets exposed to 10 mM glucose oscillated with a period of approximately 3 min, often superimposed with faster oscillations. Electroporation of ATP blocked all types of oscillations and elevated [Ca2+]i while delivery of ADP had no effect on oscillations. Intracellular delivery of glucose-6-phosphate or fructose-1,6-bisphosphate tended to transform slow oscillations to fast oscillations. These results demonstrate that modulation of ATP concentrations and glycolytic flux are important in development of slow oscillations.
Department of Chemistry, University of Michigan, 930 N. University Ave., Ann Arbor, MI 48109-1055, United States.
Gabriella M
GM
Dahlgren
Kerstin
K
Nolkrantz
Robert T
RT
Kennedy
D000227:Adenine Nucleotides / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D018274:Electroporation / Q000379:methods; D005635:Fructosediphosphates / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D019298:Glucose-6-Phosphate / Q000494:pharmacology; D006600:Hexosephosphates / Q000494:pharmacology*; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains
D000227:Adenine Nucleotides; D002121:Calcium Channel Blockers; D005635:Fructosediphosphates; D006600:Hexosephosphates; D019298:Glucose-6-Phosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005947:Glucose; C029063:fructose-1,6-diphosphate; D002118:Calcium