³H‐serotonin as a marker of oscillatory insulin secretion in clonal β‐cells (INS‐1)

Abstract

Serotonin release from preloaded pancreatic b-cells has been used as a marker for insulin release in studying exocytosis from single cells using the amperometric technique. We found that single pancreatic b-cells exhibited oscillations in exocytosis with a period of 1-1.5 min as measured amperometrically by serotonin release. We also show that 3 H-serotonin can be used to monitor exocytosis from intact and streptolysin-O permeabilized clonal insulin-secreting cells preloaded with labeled serotonin and that serotonin release correlated with insulin secretion in the same cells. The use of 3 H-serotonin provides a real-time indicator of exocytosis from populations of clonal insulin-secreting cells.

Transcellular Neuroligin-2 Interactions Enhance Insulin Secretion and Are Integral to Pancreatic β Cell Function

“…Briefly, cells co-cultured for 24 h were washed with KRB buffer containing 2.75 mM glucose, equilibrated in this solution for 45 min, and then permeabilized using 3.2 units/ml streptolysin-O (Sigma) for 30 min on ice as described previously (24,26). Cells were then washed and equilibrated with an EGTA-buffered 0.1 M free Ca 2ϩ , 140 mM K ϩ -glutamate solution for 10 min at 37°C and next incubated with the same EGTA-buffered solution with either 0.1 M or 10 M free Ca 2ϩ for 15 min at 37°C.…”

Effect of Tianeptine on Glucose Tolerance with Insulin Secretion in Human: Potential Anti-Diabetic Effect of the Drug

“…Findings showed that serotonin loaded into the beta cells localizes to the insulin secretory granules and is additionally co-released with it [26,27]. These authors demonstrated that there is little exocytotic activity of insulin + 5-HT at the basal glucose level, but increasing the sugar concentration results in increased insulin release from perfused beta cells.…”

“…It is incorporated into the insulin granules of the former [22,23], at which level exerts a modulatory effect [24][25][26][27]. Conversely, 5-HT facilitates the secretion of glucagon from the alpha cells into the blood stream [21,[28][29][30].…”

Co-administration of paroxetine and pravastatin causes deregulation of glucose homeostasis in diabetic rats via enhanced paroxetine exposure

“…5-HT, a marker of oscillatory insulin secretion [29] , is synthesized within β-cells and stored together with insulin in the secretory β-granules. Intracellular 5-HT regulates insulin secretion via serotonylating GTPases including Rab3a and Rab27a, which induces co-release of 5-HT and insulin [37] .…”

“…When the cells grew to 70% confluence, the cells were incu- [29,30] . The cells were collected for assaying intracellular insulin and 5-HT levels.…”