en
Scientific article
English

In vivo modulation of gap junctions and dye coupling between B-cells of the intact pancreatic islet

Published inDiabetes, vol. 32, no. 9, p. 858-868
Publication date1983
Abstract

The extent of gap junctions and dye coupling between insulin-producing B-cells was analyzed on islets of Langerhans isolated from adult rats treated for one day with glibenclamide, an insulin secretagogue, or diazoxide, a blocker of insulin release, or a combination of the two drugs. Glibenclamide treatment was associated with a marked depletion of the islet insulin content, an effect which was blocked by pretreatment of the rats with diazoxide. Diazoxide alone caused a marked increase in the plasma glucose level, and a decrease in the level of circulating insulin and in the hormone content of the B-cells. Quantitative analysis showed that (1) under control conditions, B-cells are connected by minute gap junctions (as evaluated on freeze-fracture replicas) and show a nonuniform and apparently restricted dye coupling (as determined by microinjection of the low-molecular-weight fluorescent probe Lucifer Yellow CH); (2) each of the three treatments tested significantly increased the relative and absolute gap junction area of the B-cells and the number of detectable, dye coupled B-cells per microinjection. After treatment with glibenclamide alone or with diazoxide plus glibenclamide, a 1.5-1.8-fold increase in gap junction area and a 2.7-3.7-fold increase in the number of dye-coupled B-cells were observed. In contrast, following treatment with diazoxide alone, gap junctions and dye coupling were found increased 1.8 and 8.7 times, respectively, as compared with control values.

Keywords
  • Animals
  • Blood Glucose/analysis
  • Cell Communication/drug effects
  • Cytoplasmic Granules/ultrastructure
  • Diazoxide/pharmacology
  • Freeze Fracturing
  • Glyburide/pharmacology
  • Insulin/blood
  • Intercellular Junctions/ ultrastructure
  • Islets of Langerhans/ ultrastructure
  • Male
  • Rats
Citation (ISO format)
MEDA, Paolo et al. In vivo modulation of gap junctions and dye coupling between B-cells of the intact pancreatic islet. In: Diabetes, 1983, vol. 32, n° 9, p. 858–868. doi: 10.2337/diab.32.9.858
Identifiers
ISSN of the journal0012-1797
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