The transmembrane inner ear (Tmie) protein is essential for normal hearing and balance in the zebrafish.

Little is known about the proteins that mediate mechanoelectrical transduction, the process by which acoustic and accelerational stimuli are transformed by hair cells of the inner ear into electrical signals. In our search for molecules involved in mechanotransduction, we discovered a line of deaf and uncoordinated zebrafish with defective hair-cell function. The hair cells of mutant larvae fail to incorporate fluorophores that normally traverse the transduction channels and their ears lack microphonic potentials in response to vibratory stimuli.

Synaptic homeostasis in a zebrafish glial glycine transporter mutant.

Truncated escape responses characteristic of the zebrafish shocked mutant result from a defective glial glycine transporter (GlyT1). In homozygous GlyT1 mutants, irrigating brain ventricles with glycine-free solution rescues normal swimming. Conversely, elevating brain glycine levels restores motility defects.

Tracking tagged molecules in single neurons in intact zebrafish.

INTRODUCTIONThis protocol describes an approach for monitoring the movement of tagged molecules in single neurons in intact embryonic and larval zebrafish. The intact preparation provides a meaningful context for the physiological event being studied. Other advantages offered by the young zebrafish include direct in vivo imaging, the ability to produce large numbers of labeled embryos easily using microinjection, and the existence of identified sensory circuits that can be exploited to activate a particular cell type.

A mutation in serca underlies motility dysfunction in accordion zebrafish.

Zebrafish acquire the ability for fast swimming early in development. The motility mutant accordion (acc) undergoes exaggerated and prolonged contractions on both sides of the body, interfering with the acquisition of patterned swimming responses. Our whole cell recordings from muscle indicate that the defect is not manifested in neuromuscular transmission.

Persistent electrical coupling and locomotory dysfunction in the zebrafish mutant shocked.

On initial formation of neuromuscular junctions, slow synaptic signals interact through an electrically coupled network of muscle cells. After the developmental onset of muscle excitability and the transition to fast synaptic responses, electrical coupling diminishes. No studies have revealed the functional importance of the electrical coupling or its precisely timed loss during development.