Abstract: African lungfishes are obligate air breathers, with reduced gills and pulmonary breathing throughout their
life. During the dry season they aestivate on land, with the collapse of secondary lamellae of their gills
and the establishment of an exclusive aerial ventilation through the vascularization and expansion of
their lungs. To date, the mechanisms underlining the respiratory organ remodeling in aestivating lung-
fishes are unknown. This study aimed to identify key switch components of the stress-induced signal
transduction networks implicated in both rapid and medium?long term remodeling of the gills and lungs
of the African lungfish Protopterus annectens during aestivation. Through immunofluorescence micros-
copy and Western blotting, the localization and the expression of nitric oxide synthase (NOS), Akt, Hsp-
90 and HIF-1? were evaluated in both gills and lungs exposed to three experimental conditions: freshwater
(FW), 6 months of experimentally induced aestivation (6mAe), and 6 days after arousal from 6 months
of aestivation (6mAe6d). After 6mAe, the expression of NOS (p-eNOS antibody), Akt (p-Akt antibody),
and Hsp-90 decreased in the gills, while NOS and Hsp-90 expression increased with Akt remained un-
changed in the lungs. Upon 6mAe6d, NOS, Akt and Hsp-90 expression in the gills returned to the respective
FW values. In the lungs of the aroused fish, NOS and Akt decreased to their respective FW levels, while
Hsp-90 expression was enhanced with respect to aestivation. In both respiratory organs, the qualitative
and quantitative patterns of HIF-1? expression correlated inversely to those of NOS. Overall, our find-
ings suggest that the molecular components of the NOS/NO system changed in a tissue-specific manner
in parallel with organ readjustment in the gills and lungs of P. annectens during aestivation and arousal
Autoría: Garofalo F., Amelio D., Icardo J., Chew S., Tota B., Cerra M., Ip Y.,
Fuente: Nitric Oxide, 2015, 44, 71-80
Editorial: Elsevier
Año de publicación: 2015
Nº de páginas: 10
Tipo de publicación: Artículo de Revista
DOI: 10.1016/j.niox.2014.11.017
ISSN: 1089-8603,1089-8611