Submitted on July 12, 2007
Accepted on October 23, 2007
Locomotor pattern in the adult zebrafish spinal cord in vitro
Jens Peter Gabriel1, Riyadh Mahmood1, Alexander M Walter1, Alexandros Kyriakatos1, Giselbert Hauptmann2, Ronald L. Calabrese3, and Abdeljabbar El Manira1*
1 Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
2 Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
3 Biology, Emory University, Atlanta, Georgia, United States
* To whom correspondence should be addressed. E-mail: abdel.elmanira{at}ki.se.
The zebrafish is an attractive model system for studying the function of the spinal locomotor network by combining electrophysiological, imaging and genetic approaches. Thus far, most studies have been focusing on embryonic and larval stages. In this study we have developed an in vitro preparation of the isolated spinal cord from adult zebrafish in which locomotor activity can be induced while the activity of single neurons can be monitored using whole-cell recording techniques. Application of NMDA elicited rhythmic locomotor activity that was monitored by recording from muscles or ventral roots in semi-intact or isolated spinal cord preparations, respectively. This rhythmic activity displayed a left-right alternation and a rostro-caudal delay. Blockade of glycinergic synaptic transmission by strychnine switched the alternating activity into synchronous bursting in the left and right sides as well as along the rostro-caudal axis. Whole-cell recordings from motoneurons showed that they receive phasic synaptic inputs that were correlated with the locomotor activity recorded in ventral roots. This newly developed in vitro preparation of the adult zebrafish spinal cord will allow the examination of the organization of the spinal locomotor network in an adult system to complement studies in zebrafish larvae and new born rodents.
