Carbon dioxide chemoreception and the cardioventilatory effects of hypercarbia in fish.

• Main Author: McKendry, John E.
• Other Authors: Perry, Steve
• Format: Thesis
• Language: unknown
• Published: University of Ottawa (Canada) 2001
• Subjects: Biology; Animal Physiology; Pacific; Atlantic salmon; Salmo salar; spiny dogfish; Squalus acanthias
• Online Access: http://hdl.handle.net/10393/8996; https://doi.org/10.20381/ruor-7590

In situ and in vivo experiments were performed on rainbow trout (Oncorhynchus mykiss) to examine (i) the direct effect of CO2 on the systemic vasculature and (ii) the influence of internal versus external hypercarbic acidosis on a variety of cardiovascular variables. Adult Atlantic salmon (Salmo salar) were exposed to acute, localized environmental hypercarbia (2.0 and 4.0% CO2 in air) over the gills via injections (60 ml/kg) of equilibrated seawater directly into the buccal cavity. Adult Atlantic salmon (Salmo salar) and Pacific spiny dogfish (Squalus acanthias) were exposed to acute environmental hypercarbia (approximately 20 min). Experiments were performed to examine the influence of environmental hypercarbia on aspects of cardiorespiratory physiology, and in separate series of experiments the muscarinic antagonist atropine (100 nmol kg-1; both species) and complete branchial denervation (dogfish) were used to investigate putative CO2-chemoreceptive sites on the gills and their link to the autonomic nervous system. The homogeneity of the cardiovascular and ventilatory responses amongst fish to elevated ambient CO2 was investigated by exposing six species of fish to acute environmental hypercarbia (approximately 20 min). The experiments were performed in vivo using two marine teleosts, Atlantic salmon (Salmo salar) and Pacific sanddab (Citharychthus sordidus); two freshwater teleosts, brown bullhead (Ictalurus nebulosus) and American eel (Anguilla rostrata); as well as one marine elasmobranch, the Pacific spiny dogfish (Squalus acanthias). (Abstract shortened by UMI.)