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Effects of Acute Temperature Change on Cardiac Performance and Oxygen Consumption of a Marine Fish, the Sea Raven (Hemitripterus americanus)

1989; University of Chicago Press; Volume: 62; Issue: 5 Linguagem: Inglês

10.1086/physzool.62.5.30156198

1937-4267

John R. Bailey, William R. Driedzic,

Marine Bivalve and Aquaculture Studies

Sea ravens (Hemitripterus americanus), subjected to a temperature transition from 10° to 5° C over a 3-h period, showed a decrease in ventral aortic pressure from 42 to 18 cmH₂0 and a decrease in heart rate from 31 to 14 bpm. Isolated hearts, per-fused at 10° C with media containing 1 mM CaCl₂, were able to perform as well as in vivo hearts. When the in vitro preparation was taken from 10° to 5° C there was a small but significant decrease in performance and oxygen consumption over frequencies ranging from 12 to 48 bpm. The decrease in function in vivo was much more substantial than could be accounted for by the direct impact of temperature on the isolated heart. The small but significant decrease in performance by the isolated heart was not due to an impairment of energy-production mechanisms or limited extracellular calcium, as an increase in extracellular calcium resulted in an increase in oxygen consumption with no alteration in contractile performance.