A role for nitric oxide in the control of breathing in zebrafish (Danio rerio).
Nitric oxide (NO) is a gaseous neurotransmitter, which, in adult mammals, modulates the acute hypoxic ventilatory response; its role in the control of breathing in fish during development is unknown. We addressed the interactive effects of developmental age and NO in the control of piscine breathing by measuring the ventilatory response of zebrafish (Danio rerio) adults and larvae to NO donors and by inhibiting endogenous production of NO. In adults, sodium nitroprusside (SNP), a NO donor, inhibited ventilation; the extent of the ventilatory inhibition was related to the pre-existing ventilatory drive, with the greatest inhibition exhibited during exposure to hypoxia (PO2=5.6 kPa). Inhibition of endogenous NO production using L-NAME suppressed the hypoventilatory response to hyperoxia, supporting an inhibitory role of NO in adult zebrafish. Neuroepithelial cells (NECs), the putative oxygen chemoreceptors of fish, contain neuronal nitric oxide synthase (nNOS). In zebrafish larvae at 4 days post-fertilization, SNP increased ventilation in a concentration-dependent manner. Inhibition of NOS activity with L-NAME or knockdown of nNOS inhibited the hypoxic (PO2=3.5 kPa) ventilatory response. Immunohistochemistry revealed the presence of nNOS in the NECs of larvae. Taken together, these data suggest that NO plays an inhibitory role in the control of ventilation in adult zebrafish, but an excitatory role in larvae.
Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
Cosima S
CS
Porteus
Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
Jacob
J
Pollack
Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
Velislava
V
Tzaneva
Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
Raymond W M
RW
Kwong
Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
Yusuke
Y
Kumai
Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
Sara J
SJ
Abdallah
Department of Food and Environmental Science, Messina University, Messina, I-98166, Italy.
Giacomo
G
Zaccone
Department of Food and Environmental Science, Messina University, Messina, I-98166, Italy.
Eugenia Rita
ER
Lauriano
Department of Zoology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4.
William K
WK
Milsom
Department of Biology, University of Ottawa, Ottawa, ON, Canada K1N 6N5 sfperry@uottawa.ca.
Steve F
SF
Perry
D000818:Animals; D015687:Cell Hypoxia; D002628:Chemoreceptor Cells / Q000502:physiology; D005880:Gills / Q000502:physiology; D007814:Larva / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D046569:Neuroepithelial Cells / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052248:Nitric Oxide Synthase Type I / Q000032:analysis; D009599:Nitroprusside / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism*; D015027:Zebrafish / Q000502:physiology*
D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D010100:Oxygen; D019331:NG-Nitroarginine Methyl Ester
Chemoreceptor; Hyperoxia; Hypoxia; Immunohistochemistry; Morpholino; Neuroepithelial cell