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Na+, K+-ATPase 2 subunit gene (Atp1a2) knock-out homozygous mice (Atp1a2-/-) died immediately after birth resulting from lack of breathing. The respiratory-related neuron activity in Atp1a2-/- was investigated using a brainstem-spinal cord en bloc preparation. The respiratory motoneuron activity recorded from the fourth cervical ventral root (C4) was(More)
Six1 is a member of the Six family homeobox genes, which function as components of the Pax-Six-Eya-Dach gene network to control organ development. Six1 is expressed in otic vesicles, nasal epithelia, branchial arches/pouches, nephrogenic cords, somites and a limited set of ganglia. In this study, we established Six1-deficient mice and found that development(More)
The sodium pump is the enzyme responsible for the maintenance of Na+ and K+ gradients across the cell membrane. Four isoforms of the catalytic alpha subunit have been identified, but their individual roles remain essentially unknown. To investigate the necessary functions of the alpha2 subunit in vivo, we generated and analyzed mice defective in the alpha2(More)
Phox2b protein is a specific marker for neurons in the parafacial region of the ventral medulla, which are proposed to play a role in central chemoreception and postnatal survival. Mutations of PHOX2B cause congenital central hypoventilation syndrome. However, there have been no reports concerning electrophysiological characteristics of these(More)
All cranial sensory organs and sensory neurons of vertebrates develop from cranial placodes. In chick, amphibians and zebrafish, all placodes originate from a common precursor domain, the pre-placodal region (PPR), marked by the expression of Six1/4 and Eya1/2. However, the PPR has never been described in mammals and the mechanism involved in the formation(More)
The olfactory epithelium (OE) is derived from the olfactory placode (OP) during mouse development. At embryonic day (E) 10.0-E10.5, "early neurogenesis" occurs in the OE, which includes production of pioneer neurons that emigrate out of the OE and other early-differentiated neurons. Around E12.5, the OE becomes organized into mature pseudostratified(More)
Survival of sensory neurons is tightly regulated in cell-type and developmental-stage-specific manners. The transcriptional regulatory mechanisms underlying this regulation remain to be elucidated. In the present study, we investigated the role of Six1 and Six4 in the development of trigeminal ganglia. Abundant expression of Six1 and Six4 was noted in(More)
The current concept regarding the respiratory centre in mammals is that it is composed of two distinct rhythm-generating neuronal networks in the ventrolateral medulla. These two rhythm generators can be active independently but are normally coupled in newborn and juvenile rats. Detailed characteristics of each generator and the neuronal mechanisms of(More)
The parafacial respiratory group (pFRG) in the rostral ventrolateral medulla of the newborn rat is predominantly composed of pre-inspiratory (Pre-I) neurons and is involved in respiratory rhythm generation. The subgroup located close to the ventral surface (at least partially overlapping the retrotrapezoid nucleus, RTN) expresses the Phox2b transcription(More)
Using the method of gene targeting in mouse embryonic stem cells, regulatory function of ␦ EF1, a zinc finger and homeodomain-containing transcription factor, was investigated in vivo by generating the ␦ EF1 mutant mice. The mutated allele of ␦ EF1 produced a truncated form of the ␦ EF1 protein lacking a zinc finger cluster proximal to COOH terminus. The(More)