Cardiac influence of the ß3-adrenoceptor in the goldfish (Carassius auratus): a protective role under hypoxia?
J Exp Biol
; 222(Pt 19)2019 10 10.
Article
en En
| MEDLINE
| ID: mdl-31527180
ABSTRACT
The goldfish (Carassius auratus) exhibits a remarkable capacity to survive and remain active under prolonged and severe hypoxia, making it a good model for studying cardiac function when oxygen availability is a limiting factor. Under hypoxia, the goldfish heart increases its performance, representing a putative component of hypoxia tolerance; however, the underlying mechanisms have not yet been elucidated. Here, we aimed to investigate the role of ß3-adrenoreceptors (ARs) in the mechanisms that modulate goldfish heart performance along with the impact of oxygen levels. By western blotting analysis, we found that the goldfish heart expresses ß3-ARs, and this expression increases under hypoxia. The effects of ß3-AR stimulation were analysed by using an ex vivo working heart preparation. Under normoxia, the ß3-AR-selective agonist BRL37344 (10-12 to 10-7 molâ
l-1) elicited a concentration-dependent increase of contractility that was abolished by a specific ß3-AR antagonist (SR59230A; 10-8 molâ
l-1), but not by α/ß1/ß2-AR inhibitors (phentolamine, nadolol and ICI118,551; 10-7 molâ
l-1). Under acute hypoxia, BRL37344 did not affect goldfish heart performance. However, SR59230A, but not phentolamine, nadolol or ICI118,551, abolished the time-dependent enhancement of contractility that characterizes the hypoxic goldfish heart. Under both normoxia and hypoxia, adenylate cyclase and cAMP were found to be involved in the ß3-AR-dependent downstream transduction pathway. In summary, we show the presence of functional ß3-ARs in the goldfish heart, whose activation modulates basal performance and contributes to a hypoxia-dependent increase of contractility.
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Texto completo:
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Bases de datos:
MEDLINE
Asunto principal:
Carpa Dorada
/
Receptores Adrenérgicos beta 3
/
Corazón
/
Hipoxia
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
J Exp Biol
Año:
2019
Tipo del documento:
Article
País de afiliación:
Italia