ZFIN ID: ZDB-PUB-121010-18
β-Adrenergic regulation of Na+ uptake by larval zebrafish Danio rerio in acidic and ion-poor environments
Kumai, Y., Ward, M., and Perry, S.F.
Date: 2012
Source: American journal of physiology. Regulatory, integrative and comparative physiology   303(10): R1031-1041 (Journal)
Registered Authors: Perry, Steve F.
Keywords: adrenergic receptor, ionocyte, zebrafish, acidic water, ionic regulation
MeSH Terms:
  • Adrenergic beta-Agonists/pharmacology
  • Adrenergic beta-Antagonists/pharmacology
  • Animals
  • Catecholamines
  • Hydrocortisone
  • Hydrogen-Ion Concentration
  • Ions
  • Larva
  • Receptors, Adrenergic, beta/metabolism*
  • Sodium/metabolism*
  • Water/chemistry
  • Zebrafish
PubMed: 23019213 Full text @ Am. J. Physiol. Regul. Integr. Comp. Physiol.
ABSTRACT

The potential role of adrenergic systems in regulating Na+ uptake in zebrafish (Danio rerio) larvae was investigated. Treatment with isoproterenol (a generic β-adrenergic receptor agonist) stimulated Na+ uptake, whereas treatment with phenylephrine (an α1-adrenergic receptor agonist) or clonidine (an α2-adrenergic receptor agonist) significantly reduced Na+ uptake, suggesting opposing roles of α- and β-adrenergic receptors in Na+ uptake regulation. The increase in Na+ uptake associated with exposure to acidic water (pH = 4.0), was attenuated in the presence of the non-selective β-receptor antagonist propranolol or the β1-receptor blocker atenolol; the β2-receotor antagonist ICI-118551 was without effect. The stimulation of Na+ uptake associated with ion-poor water (32-fold dilution of Ottawa tapwater) was unaffected by β-receptor blockade. Translational gene knockdown of β-receptors using antisense oligonucleotide morpholinos was used as a second method to assess the role of adrenergic systems in the regulation of Na+ uptake. Whereas β1- or β2B-receptor knockdown led to significant decreases in Na+ uptake during exposure to acidic water, only β2A-receptor morphants failed to increase Na+ uptake in response to ion-poor water. In support of the pharmacology and knockdown experiments that demonstrated an involvement of β-adrenergic systems in the control of Na+ uptake, we showed that the H+-ATPase rich (HR) cell, a subtype of ionocyte known to be a site of Na+ uptake, is innervated and appears to express β-adrenergic receptors (propranolol binding sites) at 4 days post fertilization (dpf). These data indicate an important role of adrenergic systems in regulating Na+ uptake in developing zebrafish.

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