Abstract
In order to understand the mechanism how the visceral information is transmitted to the brain, it is indispensable to identify the roles played by already-identified molecules in the synaptic transmission between the vagal afferent fibers and the second-order neurons in the nucleus tractus solitarii (NTS). The molecules underlying the regulation of transmitter release at this synapse are synthesized in the cell bodies located in the nodose ganglion (NG). Here we challenged to establish an optimized method for efficient in-vivo gene transfer into the NG neurons and evaluated expression of the gene product in the NG and its centrally projecting axons. In young Wistar rats, electrical pulses optimized for electroporation were delivered to the NG immediately following injection of pCAGGS-EGFP plasmid vector (5 μg/μl; through courtesy of Drs. J. Miyazaki and K. Nakajima). Two days after delivery, the NG was dissected out and fixed in 4% paraforaldehyde. In some cases, acute brainstem slices including the NTS were prepared and examined with a confocal microscopy a few weeks later. A large portion of somata in the NG and a large number of fibers projecting from NG expressed EGFP. EGFP fluorescence was also detected in the solitary tract and presynaptic termini in the NTS in the brainstem slices. This technique might be applicable to analyzing specific molecule function in the transmitter release in the central termini of the visceral afferent nerves. [J Physiol Sci. 2006;56 Suppl:S173]
