Abstract
Enkephalinergic neurons have been found in several areas of the central nervous system (CNS), including the spinal cord. In the spinal cord, neurons containing enkephalin exist mainly in the superficial laminae of the dorsal horn, and play an important role in the transmission and modulation of nociceptive information. To investigate the functional roles of enkephalinergic neurons in the CNS, we attempted to visualize enkephalinergic neurons in vivo. We first generated Bacterial Artificial Chromosome (BAC) transgenic mouse, in which enhanced green fluorescent protein (EGFP) is expressed in enkephalinergic neurons under the control of the preproenkephalin gene (penk) promoter. A BAC-penk-EGFP transgenic vector that has inserted EGFP in a penk gene locus was constructed by using a BAC recombination system (λ-Red recombination system). Immunohistochemical studies indicated that in the CNS, the expression pattern of EGFP is similar to that of endogenous enkephalin. This transgenic mouse allowed us to identify enkephalinergic neurons in vivo. [J Physiol Sci. 2007;57 Suppl:S156]
