8330 Pancreatic neurons in neuron-islet complexes and activation of these neurons promotes insulin secretion under high glucose level

Abstract Disclosure: Y. Liu: None. Z. Yang: None. Q. Feng: None. M. Hu: None. L. Sha: None. Islets are rich in pancreatic nerve innervation. Pancreatic ganglionic neurons, as an integrating center, receive central and peripheral nerve innervation regulating endocrine and exocrine of pancreas. Neurons in pancreatic ganglia have been studied intensely in our lab and a few other labs. Neurons located in islets forming neuron-islet complexes have been demonstrated. However, the properties and function of these neurons has not been studied. In this study, pancreatic neurons in the neuron-islet complex and the effects of activation of these neurons on insulin release were investigated. Methods: Eight week old rats were used. Pancreas was digested and a method was developed to identify neuron-islet complexes from islets. Results: CHAT and TUBB3 were co-localized in nearly all neurons in the neuron-islet complex indicating that these neurons were mainly cholinergic neurons. A small portion (<10%) of TUBB3 positive cells were also positive for nNOS. Nicotinic tartrate was used to activate neurons in the complexes. After one hour of administration of nicotinic tartrate, with 5.6 mM glucose, ACh level was increased significantly from 15.26±5.46 μM to 23.24±4.18 μM and insulin level were slightly increased from 37.21±2.04 μM to 39.27±1.23μM (P > 0.05). With 16.7 mM glucose, ACh level were increased significantly from 23.83±2.28 μM to 30.92±1.03 μM and insulin increased significantly from 41.93±1.30 μM to 49.04±1.68 μM. Conclusion: The neurons in neuron-islet complexes are mainly cholinergic neurons and activation of these neuron under high glucose level stimulate insulin secretion. Presentation: 6/2/2024