抄録
The terminal nerve (TN)-gonadotropin releasing hormone (GnRH) neurons are suggested to release GnRH peptides from widely branched neural processes and the somatodendritic regions, depending on their firing activity, and the released GnRH is suggested to exert their neuromodulatory action on GnRH receptors located on various target neurons.To address questions on how electrical activities of the TN-GnRH neuronal somata affect GnRH release from various neuronal compartments, we established the primary culture of TN-GnRH neurons, which will enable simultaneous recordings of various physiological signals from various compartments of a single TN-GnRH neuron.The whole brain of an adult freshwater fish (dwarf gourami) was dissected out, and the TN-GnRH neurons were sucked out from the brain with the aid of a suction pipette and plated on a coverslip in culture medium. The isolated TN-GnRH neurons could be cultured up to two weeks. During the culture, the neurons grew both axon- and dendrite-like neurites. Although the cultured neurons had relatively shallow resting membrane potentials and had no spontaneous discharge, unlike the neurons in situ, they showed subthreshold spontaneous membrane potential oscillations and could be induced to fire in phasic or tonic patterns. In addition, stimulus-induced exocytotic events could be observed at the soma and neurites by using fluorescent dye, FM1-43. Therefore, isolated culture of TN-GnRH neuron will open up a wide range of possibilities for studying cellular mechanism of the exocytosis and generation of spontaneous firing activity of peptidergic neurons. [J Physiol Sci. 2008;58 Suppl:S137]
