Short-term Hypoxia Transiently Increases Dopamine β-Hydroxylase Immunoreactivity in Glomus Cells of the Rat Carotid Body

Abstract

SummaryUnder long-term hypoxia, noradrenaline (NA) content in the carotid body (CB) increases, suggesting that NA plays an important role in CB chemotransduction. However, it is unknown whether short-term hypoxia upregulates NA biosynthesis in CB. Therefore, we examined dopamine β-hydroxylase (DBH) expression in the CB of rats exposed to hypoxia (10% O 2 ) for 0 to 24 hr with immunoblotting and immunohistochemistry. Using immunoblotting, the signal intensity for DBH appeared to be the most intense in rats exposed to hypoxia for 12 hr. Using immunohistochemistry, DBH immunoreactivity was observed in the cytoplasm of some glomus cells and varicosities in controls and rats exposed to hypoxia for 6 hr. In rats exposed to hypoxia for 12 hr, DBH immunoreactive intensities in DBH-positive glomus cells were significantly higher compared with controls (p<0.05). In the CB of rats exposed to hypoxia for 18 and 24 hr, DBH immunoreactive intensities in DBH-positive glomus cells were significantly lower than that of rats exposed to hypoxia for 12 hr (p<0.05). These results demonstrate that DBH immunoreactivity is transiently increased in glomus cells by short-term hypoxia, suggesting that NA biosynthesis is transiently facilitated in glomus cells at an early stage of hypoxia. (J Histochem Cytochem 61:55-62, 2013)

Three-dimensional architectures of P2X2-/P2X3-immunoreactive afferent nerve terminals in the rat carotid body as revealed by confocal laser scanning microscopy

“…TH and S100 have been used as markers of type I and type II cells, respectively (Habeck and Kummer 1993;Kondo et al 1982). DBH immunoreactivity has also been observed in some type I cells and sympathetic nerve fibers in the CB (Kato et al 2013). Bassoon is a presynaptic active zone molecule (Schoch and Gundelfinger 2006).…”

Vesicular nucleotide transporter‐immunoreactive type I cells associated with P2X3‐immunoreactive nerve endings in the rat carotid body

“…For double or triple immunofluorescence, sections were incubated with a mixture of the antibody for VNUT and that for the Synaptophysin (SYN, Frontier Institute, Sapporo, Japan), S100B (Sigma‐Aldrich, Saint Louis, MO), P2X3 purinoceptor (Neuromics, Edina, MN), TH (Merck Millipore), DBH (Merck Millipore), Bassoon (ENZO Life Sciences, Farmingdale, NY), and S100 (DAKO Cytomation, Glostrup, Denmark). An antibody for SYN has been used as the marker of type I cells (Habeck & Kummer, ; Kato, Yokoyama, Yamaguchi‐Yamada, & Yamamoto, ), while those for S100B and S100 have been used as markers of type II cells (Kondo, Iwanaga, & Nakajima, ). An antibody for P2X3 has been used to visualize sensory nerve endings in the rat CB (Prasad et al, ).…”

“…Intense immunoreactivity for TH has been observed in a few type I cells, while weak immunoreactivity has been observed in some cells and nerve fibers in the CB of rats under normoxic condition (Kato, Yamaguchi‐Yamada, & Yamamoto, ). Immunoreactivity for DBH has been observed in some type I cells and sympathetic nerve fibers in the CB (Kato et al, ; Yokoyama et al, ). Bassoon is a presynaptic active zone molecule (Schoch & Gundelfinger, ).…”

Molecular and cellular mechanisms of the organogenesis and development of the mammalian carotid body

“…DBH is a hallmark protein for noradrenergic cells and catalyzes the conversion of dopamine into noradrenaline. Expression of DBH is known in the glomus cells after birth but its appearance in the fetal carotid body remains to be elucidated . The localizations of met‐ and leu‐enkephalins in the glomus cells have been observed in mature animals of various species at both the light and electron microscopic levels .…”