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A Phox2b BAC Transgenic Rat Line Useful for Understanding Respiratory Rhythm Generator Neural Circuitry.

Ikeda K, Takahashi M, Sato S, Igarashi H, Ishizuka T, Yawo H, Arata S, Southard-Smith EM, Kawakami K, Onimaru H - PLoS ONE (2015)

Bottom Line: Here we describe the generation of a novel transgenic (Tg) rat harboring fluorescently labeled Pre-I neurons in the RTN/pFRG.In addition, the Tg rat showed fluorescent signals in autonomic enteric neurons and carotid bodies.Because the Tg rat expresses inducible Cre recombinase in PHOX2B-positive cells during development, it is a potentially powerful tool for dissecting the entire picture of the respiratory neural network during development and for identifying the CO2/O2 sensor molecules in the adult central and peripheral nervous systems.

View Article: PubMed Central - PubMed

Affiliation: Division of Biology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan; Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan.

ABSTRACT
The key role of the respiratory neural center is respiratory rhythm generation to maintain homeostasis through the control of arterial blood pCO2/pH and pO2 levels. The neuronal network responsible for respiratory rhythm generation in neonatal rat resides in the ventral side of the medulla and is composed of two groups; the parafacial respiratory group (pFRG) and the pre-Bötzinger complex group (preBötC). The pFRG partially overlaps in the retrotrapezoid nucleus (RTN), which was originally identified in adult cats and rats. Part of the pre-inspiratory (Pre-I) neurons in the RTN/pFRG serves as central chemoreceptor neurons and the CO2 sensitive Pre-I neurons express homeobox gene Phox2b. Phox2b encodes a transcription factor and is essential for the development of the sensory-motor visceral circuits. Mutations in human PHOX2B cause congenital hypoventilation syndrome, which is characterized by blunted ventilatory response to hypercapnia. Here we describe the generation of a novel transgenic (Tg) rat harboring fluorescently labeled Pre-I neurons in the RTN/pFRG. In addition, the Tg rat showed fluorescent signals in autonomic enteric neurons and carotid bodies. Because the Tg rat expresses inducible Cre recombinase in PHOX2B-positive cells during development, it is a potentially powerful tool for dissecting the entire picture of the respiratory neural network during development and for identifying the CO2/O2 sensor molecules in the adult central and peripheral nervous systems.

No MeSH data available.


Related in: MedlinePlus

EYFP fluorescence is evident in known sites of Phox2b/PHOX2B expression among E14.5 Phox2b-EYFP/CreERT2 Tg rat embryos.A, C, D, Flat-mount preparation of the midbrain and hindbrain of fluorescent-positive E14.5 embryo. The signals in the III and IV motor nuclei and LoC are weaker than those of E12.5 shown in Fig 3. The dorsal migratory trajectories of motor neurons of V and VII are clearly evident in D (arrowhead). B, Superposition of figures under white-light and fluorescence of A. E, Coronal thick section (~100 μm) at the level of cardiac primodia (ca). Axons of the vagus (Xth) enter the developing cardiac primodia (arrows). The sympathetic ganglionic chain (s) are fluorescent-positive. F, Fluorescent-positive enteric nervous system progenitors derived from enteric neural crest cells are seen in the rat E14.5 intestine. The inset shows magnified views of the intestine.
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pone.0132475.g004: EYFP fluorescence is evident in known sites of Phox2b/PHOX2B expression among E14.5 Phox2b-EYFP/CreERT2 Tg rat embryos.A, C, D, Flat-mount preparation of the midbrain and hindbrain of fluorescent-positive E14.5 embryo. The signals in the III and IV motor nuclei and LoC are weaker than those of E12.5 shown in Fig 3. The dorsal migratory trajectories of motor neurons of V and VII are clearly evident in D (arrowhead). B, Superposition of figures under white-light and fluorescence of A. E, Coronal thick section (~100 μm) at the level of cardiac primodia (ca). Axons of the vagus (Xth) enter the developing cardiac primodia (arrows). The sympathetic ganglionic chain (s) are fluorescent-positive. F, Fluorescent-positive enteric nervous system progenitors derived from enteric neural crest cells are seen in the rat E14.5 intestine. The inset shows magnified views of the intestine.

Mentions: We also examined the E14.5 Tg embryos (n = 3). The signals in the III and IV motor nuclei and the locus coeruleus were still found but became weaker than those of E12.5 (Fig 4A, 4B and 4C; III, IV, LoC). Medially branched signals, which should reflect dorsal migratory trajectories of motor neurons of V and VII, were clearly observed; neurons of VII born in r4 (Fig 3C) migrated caudally through r5/r6 and turned dorsally (arrowhead in Fig 4D). Axons of the Xth motor neurons (arrows in Fig 4E) that entered into the developing cardiac primodia (Fig 4E, ca) were fluorescent-positive. The sympathetic chain was also fluorescent-positive (Fig 4E, s)


A Phox2b BAC Transgenic Rat Line Useful for Understanding Respiratory Rhythm Generator Neural Circuitry.

Ikeda K, Takahashi M, Sato S, Igarashi H, Ishizuka T, Yawo H, Arata S, Southard-Smith EM, Kawakami K, Onimaru H - PLoS ONE (2015)

EYFP fluorescence is evident in known sites of Phox2b/PHOX2B expression among E14.5 Phox2b-EYFP/CreERT2 Tg rat embryos.A, C, D, Flat-mount preparation of the midbrain and hindbrain of fluorescent-positive E14.5 embryo. The signals in the III and IV motor nuclei and LoC are weaker than those of E12.5 shown in Fig 3. The dorsal migratory trajectories of motor neurons of V and VII are clearly evident in D (arrowhead). B, Superposition of figures under white-light and fluorescence of A. E, Coronal thick section (~100 μm) at the level of cardiac primodia (ca). Axons of the vagus (Xth) enter the developing cardiac primodia (arrows). The sympathetic ganglionic chain (s) are fluorescent-positive. F, Fluorescent-positive enteric nervous system progenitors derived from enteric neural crest cells are seen in the rat E14.5 intestine. The inset shows magnified views of the intestine.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4492506&req=5

pone.0132475.g004: EYFP fluorescence is evident in known sites of Phox2b/PHOX2B expression among E14.5 Phox2b-EYFP/CreERT2 Tg rat embryos.A, C, D, Flat-mount preparation of the midbrain and hindbrain of fluorescent-positive E14.5 embryo. The signals in the III and IV motor nuclei and LoC are weaker than those of E12.5 shown in Fig 3. The dorsal migratory trajectories of motor neurons of V and VII are clearly evident in D (arrowhead). B, Superposition of figures under white-light and fluorescence of A. E, Coronal thick section (~100 μm) at the level of cardiac primodia (ca). Axons of the vagus (Xth) enter the developing cardiac primodia (arrows). The sympathetic ganglionic chain (s) are fluorescent-positive. F, Fluorescent-positive enteric nervous system progenitors derived from enteric neural crest cells are seen in the rat E14.5 intestine. The inset shows magnified views of the intestine.
Mentions: We also examined the E14.5 Tg embryos (n = 3). The signals in the III and IV motor nuclei and the locus coeruleus were still found but became weaker than those of E12.5 (Fig 4A, 4B and 4C; III, IV, LoC). Medially branched signals, which should reflect dorsal migratory trajectories of motor neurons of V and VII, were clearly observed; neurons of VII born in r4 (Fig 3C) migrated caudally through r5/r6 and turned dorsally (arrowhead in Fig 4D). Axons of the Xth motor neurons (arrows in Fig 4E) that entered into the developing cardiac primodia (Fig 4E, ca) were fluorescent-positive. The sympathetic chain was also fluorescent-positive (Fig 4E, s)

Bottom Line: Here we describe the generation of a novel transgenic (Tg) rat harboring fluorescently labeled Pre-I neurons in the RTN/pFRG.In addition, the Tg rat showed fluorescent signals in autonomic enteric neurons and carotid bodies.Because the Tg rat expresses inducible Cre recombinase in PHOX2B-positive cells during development, it is a potentially powerful tool for dissecting the entire picture of the respiratory neural network during development and for identifying the CO2/O2 sensor molecules in the adult central and peripheral nervous systems.

View Article: PubMed Central - PubMed

Affiliation: Division of Biology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan; Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan.

ABSTRACT
The key role of the respiratory neural center is respiratory rhythm generation to maintain homeostasis through the control of arterial blood pCO2/pH and pO2 levels. The neuronal network responsible for respiratory rhythm generation in neonatal rat resides in the ventral side of the medulla and is composed of two groups; the parafacial respiratory group (pFRG) and the pre-Bötzinger complex group (preBötC). The pFRG partially overlaps in the retrotrapezoid nucleus (RTN), which was originally identified in adult cats and rats. Part of the pre-inspiratory (Pre-I) neurons in the RTN/pFRG serves as central chemoreceptor neurons and the CO2 sensitive Pre-I neurons express homeobox gene Phox2b. Phox2b encodes a transcription factor and is essential for the development of the sensory-motor visceral circuits. Mutations in human PHOX2B cause congenital hypoventilation syndrome, which is characterized by blunted ventilatory response to hypercapnia. Here we describe the generation of a novel transgenic (Tg) rat harboring fluorescently labeled Pre-I neurons in the RTN/pFRG. In addition, the Tg rat showed fluorescent signals in autonomic enteric neurons and carotid bodies. Because the Tg rat expresses inducible Cre recombinase in PHOX2B-positive cells during development, it is a potentially powerful tool for dissecting the entire picture of the respiratory neural network during development and for identifying the CO2/O2 sensor molecules in the adult central and peripheral nervous systems.

No MeSH data available.


Related in: MedlinePlus