Functional neuronal ionotropic glutamate receptors are expressed in the non-neuronal cell line MIN6.

W e report that a non-neuronal cell line, MIN6, derived from insulin-secreting pancreatic p-cells, naturally expresses functional ionotropic glutamate receptors. Electrophysiological recordings show that kainate, a-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), and N-methyh-aspartate (NMDA) depolarize single MING cells and evoke inward ionic currents. These agents also increase the intracellular calcium concentration in MING cells. Furthermore, insulin secretion from MING cells is stimulated by kainate, AMPA, and NMDA. The presence of AMPAkainate and NMDA receptor subtypes is confirmed by reverse transcriptase-polymerase chain reaction. These results demonstrate that ionotropic glutamate receptors with properties similar to those in neuronal cells are expressed in a non-neuronal cell line, MIN6. Thus, MIN6 provides a useful and valuable model system for biochemical, pharmacological, and physiological studies of ionotropic glutamate receptors. Glutamate receptors are the major neurotransmitter receptors mediating synaptic transmission in the vertebrate central nervous system. Glutamate receptors play pivotal roles in synaptic plasticity, neuronal development, and some neurodegenerative disorders (1-5).Although glutamate receptors have been studied extensively in the central nervous system, little is known of the glutamate receptors in non-neuronal cells. It has been shown that functional ionotropic glutamate receptors are Ministry of Education, Science, and Culture and from the Ministry of