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The zebrafish is a popular model for developmental studies due to its accessibility by cellular, molecular and genetic approaches. As a complement to these other methods, we have devised an exposed hindbrain/spinal cord preparation in the curarized zebrafish embryo and larva that permits intracellular labeling and patch clamp recording from individually(More)
Bilateral alternation of muscle contractions requires reciprocal inhibition between the two sides of the hindbrain and spinal cord, and disruption of this inhibition should lead to simultaneous activation of bilateral muscles. At 1 day after fertilization, wild-type zebrafish respond to mechanosensory stimulation with multiple fast alternating trunk(More)
The development and properties of locomotor behaviors in zebrafish embryos raised at 28.5 degrees C were examined. When freed from the chorion, embryonic zebrafish showed three sequential stereotyped behaviors: a transient period of alternating, coiling contractions followed by touch-evoked rapid coils, then finally, organized swimming. The three different(More)
Zinc has been reported to potentiate glycine receptors (GlyR), but the physiological significance of this observation has been put in doubt by the relatively high values of the EC(50), 0.5-1 microM, since such concentrations may not be attained in the synaptic cleft of glycinergic synapses. We have re-evaluated this observation in the frame of the(More)
There is a need to understand the mechanisms of neural synchronization during development because correlated rhythmic activity is thought to be critical for the establishment of proper connectivity. The relative importance of chemical and electrical synapses for synchronization of electrical activity during development is unclear. We examined the activity(More)
As a first step in the study of the developing motor circuitry of the embryonic zebrafish spinal cord, we obtained patch-clamp recordings in vivo from identified motoneurons in curarized embryos from the onset of the first motor behavior. At an early developmental stage in which embryos showed slow and repetitive spontaneous contractions of the trunk,(More)
Characterizing connectivity in the spinal cord of zebrafish embryos is not only prerequisite to understanding the development of locomotion, but is also necessary for maximizing the potential of genetic studies of circuit formation in this model system. During their first day of development, zebrafish embryos show two simple motor behaviors. First, they(More)
When wild-type zebrafish embryos are touched at 24 hours post-fertilization (hpf), they typically perform two rapid alternating coils of the tail. By contrast, accordion (acc) mutants fail to coil their tails normally but contract the bilateral trunk muscles simultaneously to shorten the trunk, resulting in a pronounced dorsal bend. Electrophysiological(More)
Mutations in the gene encoding TRPM7 (trpm7), a member of the Transient Receptor Potential (TRP) superfamily of cation channels that possesses an enzymatically active kinase at its C terminus, cause the touch-unresponsive zebrafish mutant touchdown. We identified and characterized a new allele of touchdown, as well as two previously reported alleles, and(More)
General mechanisms of motor network development have often been examined in the spinal cord because of its relative simplicity when compared to higher parts of the brain. Indeed, most of our current understanding of motor pattern generation comes from work in the lower vertebrate spinal cord. Nevertheless, very little is known about the initial stages of(More)