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Neurotransmitter control of islet hormone pulsatility
Author(s) -
Gylfe E.,
Tengholm A.
Publication year - 2014
Publication title -
diabetes, obesity and metabolism
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.445
H-Index - 128
eISSN - 1463-1326
pISSN - 1462-8902
DOI - 10.1111/dom.12345
Subject(s) - somatostatin , medicine , islet , endocrinology , glucagon , paracrine signalling , neurotransmitter , insulin , insulin oscillation , biology , enteroendocrine cell , secretion , pulsatile flow , hormone , chemistry , endocrine system , central nervous system , receptor
Pulsatile secretion is an inherent property of hormone‐releasing pancreatic islet cells. This secretory pattern is physiologically important and compromised in diabetes. Neurotransmitters released from islet cells may shape the pulses in auto/paracrine feedback loops. Within islets, glucose‐stimulated β ‐cells couple via gap junctions to generate synchronized insulin pulses. In contrast, α‐ and δ‐cells lack gap junctions, and glucagon release from islets stimulated by lack of glucose is non‐pulsatile. Increasing glucose concentrations gradually inhibit glucagon secretion by α‐cell‐intrinsic mechanism/s. Further glucose elevation will stimulate pulsatile insulin release and co‐secretion of neurotransmitters. Excitatory ATP may synchronize β ‐cells with δ‐cells to generate coinciding pulses of insulin and somatostatin. Inhibitory neurotransmitters from β ‐ and δ‐cells can then generate antiphase pulses of glucagon release. Neurotransmitters released from intrapancreatic ganglia are required to synchronize β ‐cells between islets to coordinate insulin pulsatility from the entire pancreas, whereas paracrine intra‐islet effects still suffice to explain coordinated pulsatile release of glucagon and somatostatin. The present review discusses how neurotransmitters contribute to the pulsatility at different levels of integration.