Red blood cell adrenergic responses in Amazonian teleosts

A. L. Val, G. C. De Menezes, C. M. Wood

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Erythrocytes from Amazonian teleosts of the Rio Negro were surveyed for the presence of adrenergically mediated Na+/H+ exchange. Washed red blood cells (RBCs) incubated in HEPES-buffered Cortland saline were stimulated with 10-4 M L-adrenaline. The adrenergic response was clearly present in two characids, the tambaqui Colossoma macropomom and the jaraqui Semaprochilodus insignis, as demonstrated by a decrease in the pH(c)-pH(i) gradient across the RBC membrane, an uptake of Na+ from the extracellular medium, and RBC swelling. The latter was signalled by increased mean corpuscular volume (MCV) and decreased mean corpuscular haemoglobin concentration (MCHC). The response did not occur in two other characids, the black piranha Serrasalmus rhombeus and the aracu Leporinus fasciatus or in two silurid catfish, the piranambu Pinirampus pirinampu and the acari-bodo, armoured catfish, Pterygoplichthys multiradiatus. In acari-bodo, the Na+/H+ exchange response was similarly lacking under anoxic conditions. Oxygenated/deoxygenated comparisons revealed the presence of a marked Root effect in jaraqui and its absence in acari-bodo. GTP dominated over ATP as the major intracellular phosphate in all six species. There were no significant changes in any nucleoside phosphate (ATP, ADP, AMP, GTP, GDP, or GMP) in response to adrenaline in any species.

Original languageEnglish (US)
Pages (from-to)83-93
Number of pages11
JournalJournal of Fish Biology
Volume52
Issue number1
DOIs
StatePublished - Jan 1 1998

Keywords

  • Adrenaline
  • ATP
  • Characiformes
  • GTP
  • Intracellular pH
  • Na/H exchange
  • Red blood cell
  • Siluriformes

ASJC Scopus subject areas

  • Aquatic Science

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