The relationship between O-2 chemoreceptors, cardio-respiratory reflex and hypoxia tolerance in the neotropical fish Hoplias lacerdae

Author(s)

Micheli-Campbell, Mariana A. ^{[1, 2]} ; Campbell, Hamish A. ^[2] ; Kalinin, Ana L. ^{[3, 1]} ; Rantin, Francisco T. ^{[3, 1]}

Affiliation

^[1] Univ Fed Sao Carlos, Dept Physiol Sci, BR-13565905 Sao Paulo - Brazil

^[2] Univ Queensland, Sch Biol Sci, Brisbane, Qld 4072 - Australia

^[3] Natl Inst Sci & Technol Comparat Physiol FAPESP C, Sao Paulo - Brazil

• Document type: Journal article
• Source: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY; v. 154, n. 2, p. 224-232, OCT 2009.
• Web of Science Citations: 6

Abstract

The localization, distribution and orientation Of O(2) chemoreceptors associated with the control of cardiorespiratory responses were investigated in the neotropical, Hoplias lacerdae. Selective denervation of the cranial nerves (IX and X) was combined with chemical stimulation (NaCN) to characterize the gill O(2) chemoreceptors, and the fish were then exposed to gradual hypoxia to examine the extent of each cardiorespiratory response. Changes in heart rate (f(H)) and ventilation amplitude (V(amp)) were allied with chemoreceptors distributed on both internal and external surfaces of all gill arches, while ventilation rate (f(R)) was allied to the O(2) chemoreceptors located only in the internal surface of the first gill arch. H. lacerdae exposed to gradual hypoxia produced a marked bradycardia (45%) and 50% increase in V(amp), but only a relatively small change in f(R) (32%). Thus, the low f(R) response yet high V(amp) were in accord with the characterization of the O(2) chemoreceptors. Comparing these results from H. lacerdae with hypoxia-tolerant species revealed a relationship existent between general oxygenation of the individual species environment, its cardio-respiratory response to hypoxia and the characterization Of O(2) chemoreceptors. (C) 2009 Elsevier Inc. All rights reserved. (AU)