Pancreatic Endocrine Effects of Dopamine Receptors in Human Islet Cells.

Abstract

To date, there are no reports on the cellular localization of dopamine receptors in the human pancreas. In our study, we determined the localization and expression of 5 dopamine receptors (D(1), D(2), D(3), D(4), and D(5)) in normal human pancreas tissue. Human nonpathological pancreas tissues were fixed with 4% paraformaldehyde, paraffin-embedded, and processed for immunohistochemical analysis to detect dopamine receptors in the human pancreas tissue by using double immunofluorescent labeling and confocal microscopy. We found that the D(1) receptor is present in β cells; the D(2) receptor is expressed by α, δ, and pancreatic polypeptide cells; the D(4) receptor is expressed by β and polypeptide cells; whereas the D(5) receptor is expressed only by δ cells. Our results identify the dopamine receptors (D(1)-D(5)) in normal pancreas tissue and provide a morphological basis for studying the pancreatic endocrine effects of dopamine and suggest a new target for the clinical treatment of diabetes.