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Heart rate and stroke volume contribution to cardiac output in swimming yellowfin tuna: response to exercise and temperature.
J Exp Biol 1997; 200(Pt 14):1975-86JE

Abstract

Cardiac performance in the yellowfin tuna (Thunnus albacares, 673-2470 g, 33-53 cm fork length, FL) was examined in unanesthetized fish swimming in a large water tunnel. Yellowfin tuna were fitted with either electrocardiogram electrodes or a transcutaneous Doppler blood-flow probe over the ventral aorta and exposed to changes in swimming velocity (range 0.8-2.9 FLs-1) or to an acute change in temperature (18-28 degrees C). Heart rates (fH) at +/-1 degree C (30-130 beats min-1) were lower on average than previous measurements with non-swimming (restrained) tunas and comparable with those for other active teleosts at similar relative swimming velocities. Although highly variable among individuals, fH increased with velocity (U, in FLs-1) in all fish (fH = 17.93U + 49.93, r2 = 0.14, P < 0.0001). Heart rate was rapidly and strongly affected by temperature (Q10 = 2.37). Blood flow measurements revealed a mean increase in relative cardiac output of 13.6 +/- 3.0% with exercise (mean velocities 1.23-2.10 FLs-1) caused by an 18.8 +/- 5.4% increase in fH and a 3.9 +/- 2.3% decrease in stroke volume. These results indicate that, unlike most other fishes, cardiac output in yellowfin tuna is regulated primarily through increases in fH. Acute reductions in ambient temperature at slow swimming velocities resulted in decreases in cardiac output (Q10 = 1.52) and fH (Q10 = 2.16), but increases in stroke volume (Q10 = 0.78). This observation suggests that the lack of an increase in stroke volume during exercise is not due to the tuna heart operating at maximal anatomical limits.

Authors+Show Affiliations

Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla 92093-0204, USA. mblkek@centrum.dkNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

9246781

Citation

Korsmeyer, K E., et al. "Heart Rate and Stroke Volume Contribution to Cardiac Output in Swimming Yellowfin Tuna: Response to Exercise and Temperature." The Journal of Experimental Biology, vol. 200, no. Pt 14, 1997, pp. 1975-86.
Korsmeyer KE, Lai NC, Shadwick RE, et al. Heart rate and stroke volume contribution to cardiac output in swimming yellowfin tuna: response to exercise and temperature. J Exp Biol. 1997;200(Pt 14):1975-86.
Korsmeyer, K. E., Lai, N. C., Shadwick, R. E., & Graham, J. B. (1997). Heart rate and stroke volume contribution to cardiac output in swimming yellowfin tuna: response to exercise and temperature. The Journal of Experimental Biology, 200(Pt 14), pp. 1975-86.
Korsmeyer KE, et al. Heart Rate and Stroke Volume Contribution to Cardiac Output in Swimming Yellowfin Tuna: Response to Exercise and Temperature. J Exp Biol. 1997;200(Pt 14):1975-86. PubMed PMID: 9246781.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Heart rate and stroke volume contribution to cardiac output in swimming yellowfin tuna: response to exercise and temperature. AU - Korsmeyer,K E, AU - Lai,N C, AU - Shadwick,R E, AU - Graham,J B, PY - 1997/7/1/pubmed PY - 1997/7/1/medline PY - 1997/7/1/entrez SP - 1975 EP - 86 JF - The Journal of experimental biology JO - J. Exp. Biol. VL - 200 IS - Pt 14 N2 - Cardiac performance in the yellowfin tuna (Thunnus albacares, 673-2470 g, 33-53 cm fork length, FL) was examined in unanesthetized fish swimming in a large water tunnel. Yellowfin tuna were fitted with either electrocardiogram electrodes or a transcutaneous Doppler blood-flow probe over the ventral aorta and exposed to changes in swimming velocity (range 0.8-2.9 FLs-1) or to an acute change in temperature (18-28 degrees C). Heart rates (fH) at +/-1 degree C (30-130 beats min-1) were lower on average than previous measurements with non-swimming (restrained) tunas and comparable with those for other active teleosts at similar relative swimming velocities. Although highly variable among individuals, fH increased with velocity (U, in FLs-1) in all fish (fH = 17.93U + 49.93, r2 = 0.14, P < 0.0001). Heart rate was rapidly and strongly affected by temperature (Q10 = 2.37). Blood flow measurements revealed a mean increase in relative cardiac output of 13.6 +/- 3.0% with exercise (mean velocities 1.23-2.10 FLs-1) caused by an 18.8 +/- 5.4% increase in fH and a 3.9 +/- 2.3% decrease in stroke volume. These results indicate that, unlike most other fishes, cardiac output in yellowfin tuna is regulated primarily through increases in fH. Acute reductions in ambient temperature at slow swimming velocities resulted in decreases in cardiac output (Q10 = 1.52) and fH (Q10 = 2.16), but increases in stroke volume (Q10 = 0.78). This observation suggests that the lack of an increase in stroke volume during exercise is not due to the tuna heart operating at maximal anatomical limits. SN - 0022-0949 UR - https://www.unboundmedicine.com/medline/citation/9246781/Heart_rate_and_stroke_volume_contribution_to_cardiac_output_in_swimming_yellowfin_tuna:_response_to_exercise_and_temperature_ L2 - http://jeb.biologists.org/cgi/pmidlookup?view=long&amp;pmid=9246781 DB - PRIME DP - Unbound Medicine ER -