Natriuretic Peptides in Antarctic Teleosts: Cardiac
Receptors in Chionodraco hamatus and Trematomus
bernacchii
Maria C. Cerra i ,2, Rosa MazzaI, Daniela Pellegrino I, and Bruno Tota i ,3
iDepartment of Cell Biology
2Department ofPharmaco-Biology, University of Calabria, 87030 Arcavacata
di Rende, Italy
3Zoological Station "A. Dohrn," Villa Comunale, 80121 Napoli, Italy
Introduction
The myocardium of teleosts, like the atrial myocardium of homeotherm
vertebrates, is a major site of synthesis and release of various structuraly
related hormones commonly referred to as natriuretic peptides (NPs).
This family of vasorelaxant, diuretic, and natriuretic substances is
involved in both cardiovascular and body fluid homeostasis of fish [1-4].
In teleosts an increase in plasma volume is a major stimulus for NPs'
release by myocardiocytes [1], serving as an intrinsic feedback inhibitor
that protects the heart from volume overload [4]. NPs induce peripheral
vasodilation [5], associated with an in vivo reduction of cardiac output
and a decrease of the stroke volume via a direct negative inotropic action
andlor a decrease in venous return [6]. In several species of fish, NPs
have potent relaxant properties on some large vessels in an endotheliumdependent manner [7].
Two functional aspects of the Antarctic notothenioid teleosts call for a
hormonal control potentially involving NPs. The first aspect concerns
the plasma osmolality of these fishes that is higher (about 500 mosmol
kg-I) than that of other temperate marine teleosts. This is attributed to
increased NaCI concentrations [8,9] dependent on the modulation of the
renal and branchial Na+/K+ ATPases [10]. The second aspect is related
to the family Channichthyidae, or icefish, which are characterized by the
lack of hemoglobin in their blood [11]. The blood volume in icefish
(Chaenocephalus aceratus: 64-110 ml kg-l [12,13]; Chionodraco
hamatus: 127-145 ml kg-l [14]) is up to ninefold higher than in other
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998
Receptors in Chionodraco hamatus and Trematomus
bernacchii
Maria C. Cerra i ,2, Rosa MazzaI, Daniela Pellegrino I, and Bruno Tota i ,3
iDepartment of Cell Biology
2Department ofPharmaco-Biology, University of Calabria, 87030 Arcavacata
di Rende, Italy
3Zoological Station "A. Dohrn," Villa Comunale, 80121 Napoli, Italy
Introduction
The myocardium of teleosts, like the atrial myocardium of homeotherm
vertebrates, is a major site of synthesis and release of various structuraly
related hormones commonly referred to as natriuretic peptides (NPs).
This family of vasorelaxant, diuretic, and natriuretic substances is
involved in both cardiovascular and body fluid homeostasis of fish [1-4].
In teleosts an increase in plasma volume is a major stimulus for NPs'
release by myocardiocytes [1], serving as an intrinsic feedback inhibitor
that protects the heart from volume overload [4]. NPs induce peripheral
vasodilation [5], associated with an in vivo reduction of cardiac output
and a decrease of the stroke volume via a direct negative inotropic action
andlor a decrease in venous return [6]. In several species of fish, NPs
have potent relaxant properties on some large vessels in an endotheliumdependent manner [7].
Two functional aspects of the Antarctic notothenioid teleosts call for a
hormonal control potentially involving NPs. The first aspect concerns
the plasma osmolality of these fishes that is higher (about 500 mosmol
kg-I) than that of other temperate marine teleosts. This is attributed to
increased NaCI concentrations [8,9] dependent on the modulation of the
renal and branchial Na+/K+ ATPases [10]. The second aspect is related
to the family Channichthyidae, or icefish, which are characterized by the
lack of hemoglobin in their blood [11]. The blood volume in icefish
(Chaenocephalus aceratus: 64-110 ml kg-l [12,13]; Chionodraco
hamatus: 127-145 ml kg-l [14]) is up to ninefold higher than in other
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998