Differences in Ca2+-management between the ventricle of two species of neotropical teleosts: the jeju, Hoplerythrinus unitaeniatus (Spix & Agassiz, 1829), and the acara, Geophagus brasiliensis (Quoy & Gaimard, 1824)

Autor(es)

Costa, Monica Jones ^[1] ; Rantin, Francisco Tadeu ^[2] ; Kalinin, Ana Lucia ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, BR-13565905 Sorocaba, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Physiol Sci, BR-13560 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Neotropical Ichthyology; v. 7, n. 3, p. 471-478, JUL-SEP 2009.
• Citações Web of Science: 1

Resumo

This study analyzed the physiological role of the cardiac sarcoplasmic reticulum (SR) of two neotropical teleosts, the jeju, Hoplerythrinus unitaeniatus (Erythrinidae), and the acara, Geophagus brasiliensis (Cichlidae). While the in vivo heart frequency (fH - bpm) of acara (79.6 ± 6.6) was higher than that of the jeju (50.3 ± 2.7), the opposite was observed for the ventricular inotropism (Fc - mN/mm²) at 12 bpm (acara = 28.66 ± 1.86 vs. jeju = 36.09 ± 1.67). A 5 min diastolic pause resulted in a strong potentiation of Fc (≅ 90%) of strips from jeju, which was completely abolished by ryanodine. Ryanodine also resulted in a ≅ 20% decrease in the Fc developed by strips from jeju at both subphysiological (12 bpm) and physiological (in vivo) frequencies. However, this effect of ryanodine reducing the Fc from jeju was completely compensated by adrenaline increments (10-9 and 10-6 M). In contrast, strips from acara were irresponsive to ryanodine, irrespective of the stimulation frequency, and increases in adrenaline concentration (to 10-9 and 10-6 M) further increased Fc. These results reinforce the hypothesis of the functionality of the SR as a common trait in neotropical ostariophysian (as jeju), while in acanthopterygians (as acara) it seems to be functional mainly in 'athletic' species. (AU)

• Processo FAPESP: 02/14189-3 - O retículo sarcoplasmático em peixes Teleosteos: uma abordagem filogenética
• Beneficiário: Monica Jones Costa
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 03/08238-4 - O reticulo sarcoplasmatico em peixes Teleosteos: uma abordagem filogenética
• Beneficiário: Ana Lúcia Kalinin
• Modalidade de apoio: Auxílio à Pesquisa - Regular