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Dopamine modulates insulin release and is involved in the survival of rat pancreatic beta cells.

Garcia Barrado MJ, Iglesias Osma MC, Blanco EJ, Carretero Hernández M, Sánchez Robledo V, Catalano Iniesta L, Carrero S, Carretero J - PLoS ONE (2015)

Bottom Line: The secretion of insulin from isolated islets was significantly inhibited (p<0.01), by treatment with 1 and 10 μM dopamine, with no differences between either dose as early as 1 h after treatment.The percentage of insulin-positive cells in the islets decreased significantly (p<0.01) after 1 h of treatment up to 12 h.In conclusion, these results suggest that dopamine could modulate the proliferation and apoptosis of pancreatic beta cells and that dopamine may be involved in the maintenance of pancreatic islets.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, University of Salamanca, Salamanca, Spain; Laboratory of Neuroendocrinology, Institute of Neurosciences of Castilla y León, and Laboratory of Neuroendocrinology and Obesity of IBSAL, University of Salamanca, Salamanca, Spain.

ABSTRACT
The local synthesis of dopamine and its effects on insulin release have been described in isolated islets. Thus, it may be accepted that dopamine exerts an auto-paracrine regulation of insulin secretion from pancreatic beta cells. The aim of the present study is to analyze whether dopamine is a regulator of the proliferation and apoptosis of rat pancreatic beta cells after glucose-stimulated insulin secretion. Glucose stimulated pancreatic islets obtained from male Wistar rats were cultured with 1 or 10 μM dopamine from 1 to 12 h. Insulin secretion was analyzed by RIA. The cellular proliferation rate of pancreatic islets and beta cells was studied with immunocytochemical double labelling for both insulin and PCNA (proliferating cell nuclear antigen), and active caspase-3 was detected to evaluate apoptosis. The secretion of insulin from isolated islets was significantly inhibited (p<0.01), by treatment with 1 and 10 μM dopamine, with no differences between either dose as early as 1 h after treatment. The percentage of insulin-positive cells in the islets decreased significantly (p<0.01) after 1 h of treatment up to 12 h. The proliferation rate of insulin-positive cells in the islets decreased significantly (p<0.01) following treatment with dopamine. Apoptosis in pancreatic islets and beta cells was increased by treatment with 1 and 10 μM dopamine along 12 h. In conclusion, these results suggest that dopamine could modulate the proliferation and apoptosis of pancreatic beta cells and that dopamine may be involved in the maintenance of pancreatic islets.

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Related in: MedlinePlus

Inmunocytochemical analysis of insulin-positive cells in isolated islets treated with dopamine.(A) Micrographs showing some immunocytochemical staining patterns for insulin (red) in control islets (i), and dopamine-treated islets at 1, 3, 6 and 12 h (ii). (B) Plot showing the decrease induced by dopamine in the percentage of insulin-positive cells at the different time-points assayed; from 1 to 12 hours of treatment a significant decrease (*p<0.05, **p<0.01 with respect to their respective controls) was observed. Scale bar: 50 μm.
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pone.0123197.g002: Inmunocytochemical analysis of insulin-positive cells in isolated islets treated with dopamine.(A) Micrographs showing some immunocytochemical staining patterns for insulin (red) in control islets (i), and dopamine-treated islets at 1, 3, 6 and 12 h (ii). (B) Plot showing the decrease induced by dopamine in the percentage of insulin-positive cells at the different time-points assayed; from 1 to 12 hours of treatment a significant decrease (*p<0.05, **p<0.01 with respect to their respective controls) was observed. Scale bar: 50 μm.

Mentions: Insulin-positive cells were found mainly in the core of the islets (Fig 2A-i). Treatment with dopamine modified the intensity of the immunocytochemical reaction and the number and size of positive cells (Fig 2A-ii). In the control islets, the percentage of insulin-positive cells (Fig 2B) was very similar for all time-points assayed, ranging from 67± 2.5 to 66 ±2.4). In the islets treated with dopamine, the percentages of insulin-positive cells were decreased for all doses and time-points assayed (p<0.01 at 1, 3, 6 at 12 hours versus controls).


Dopamine modulates insulin release and is involved in the survival of rat pancreatic beta cells.

Garcia Barrado MJ, Iglesias Osma MC, Blanco EJ, Carretero Hernández M, Sánchez Robledo V, Catalano Iniesta L, Carrero S, Carretero J - PLoS ONE (2015)

Inmunocytochemical analysis of insulin-positive cells in isolated islets treated with dopamine.(A) Micrographs showing some immunocytochemical staining patterns for insulin (red) in control islets (i), and dopamine-treated islets at 1, 3, 6 and 12 h (ii). (B) Plot showing the decrease induced by dopamine in the percentage of insulin-positive cells at the different time-points assayed; from 1 to 12 hours of treatment a significant decrease (*p<0.05, **p<0.01 with respect to their respective controls) was observed. Scale bar: 50 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401745&req=5

pone.0123197.g002: Inmunocytochemical analysis of insulin-positive cells in isolated islets treated with dopamine.(A) Micrographs showing some immunocytochemical staining patterns for insulin (red) in control islets (i), and dopamine-treated islets at 1, 3, 6 and 12 h (ii). (B) Plot showing the decrease induced by dopamine in the percentage of insulin-positive cells at the different time-points assayed; from 1 to 12 hours of treatment a significant decrease (*p<0.05, **p<0.01 with respect to their respective controls) was observed. Scale bar: 50 μm.
Mentions: Insulin-positive cells were found mainly in the core of the islets (Fig 2A-i). Treatment with dopamine modified the intensity of the immunocytochemical reaction and the number and size of positive cells (Fig 2A-ii). In the control islets, the percentage of insulin-positive cells (Fig 2B) was very similar for all time-points assayed, ranging from 67± 2.5 to 66 ±2.4). In the islets treated with dopamine, the percentages of insulin-positive cells were decreased for all doses and time-points assayed (p<0.01 at 1, 3, 6 at 12 hours versus controls).

Bottom Line: The secretion of insulin from isolated islets was significantly inhibited (p<0.01), by treatment with 1 and 10 μM dopamine, with no differences between either dose as early as 1 h after treatment.The percentage of insulin-positive cells in the islets decreased significantly (p<0.01) after 1 h of treatment up to 12 h.In conclusion, these results suggest that dopamine could modulate the proliferation and apoptosis of pancreatic beta cells and that dopamine may be involved in the maintenance of pancreatic islets.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pharmacology, Faculty of Medicine, University of Salamanca, Salamanca, Spain; Laboratory of Neuroendocrinology, Institute of Neurosciences of Castilla y León, and Laboratory of Neuroendocrinology and Obesity of IBSAL, University of Salamanca, Salamanca, Spain.

ABSTRACT
The local synthesis of dopamine and its effects on insulin release have been described in isolated islets. Thus, it may be accepted that dopamine exerts an auto-paracrine regulation of insulin secretion from pancreatic beta cells. The aim of the present study is to analyze whether dopamine is a regulator of the proliferation and apoptosis of rat pancreatic beta cells after glucose-stimulated insulin secretion. Glucose stimulated pancreatic islets obtained from male Wistar rats were cultured with 1 or 10 μM dopamine from 1 to 12 h. Insulin secretion was analyzed by RIA. The cellular proliferation rate of pancreatic islets and beta cells was studied with immunocytochemical double labelling for both insulin and PCNA (proliferating cell nuclear antigen), and active caspase-3 was detected to evaluate apoptosis. The secretion of insulin from isolated islets was significantly inhibited (p<0.01), by treatment with 1 and 10 μM dopamine, with no differences between either dose as early as 1 h after treatment. The percentage of insulin-positive cells in the islets decreased significantly (p<0.01) after 1 h of treatment up to 12 h. The proliferation rate of insulin-positive cells in the islets decreased significantly (p<0.01) following treatment with dopamine. Apoptosis in pancreatic islets and beta cells was increased by treatment with 1 and 10 μM dopamine along 12 h. In conclusion, these results suggest that dopamine could modulate the proliferation and apoptosis of pancreatic beta cells and that dopamine may be involved in the maintenance of pancreatic islets.

Show MeSH
Related in: MedlinePlus