Cardiovascular and respiratory reflexes in the tropical fish, traira (Hoplias malabaricus): CO2/pH chemoresponses.

摘要: To examine the distribution and physiological role of CO2/pH-sensitive chemoreceptors in gills tropical fish, traira (Hoplias malabaricus), fish were exposed to acute environmental hypercarbia (1.25, 2.5 5.0% CO2 air) subjected injections HCl into ventral aorta buccal cavity. This was done before after selective denervation branchial branches IXth Xth cranial nerves various arches. Hypercarbia produced a significant decrease heart rate, mild hypotension as well increases both ventilation rate amplitude. The data suggest that hypercarbic bradycardia increase frequency arise from receptors exclusively within but present on more than first gill arch, while extra-branchial may also be involved controlling With exception response injected aorta, acid (internal external) did not mimic cardiorespiratory responses observed during suggesting changes are important pH producing responses. Finally, indicate sensitive CO2/pH O2 this species ventilatory distributed similar fashion, those not.