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.
Dahlgren
Gabriella M
GM
Department of Chemistry, University of Michigan, 930 N. University Ave., Ann Arbor, MI 48109-1055, United States.
Nolkrantz
Kerstin
K
Kennedy
Robert T
RT
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