Abstract

Time course studies are critical for understanding regulatory mechanisms and temporal constraints in ectothermic animals acclimating to warmer temperatures. Therefore, we investigated the dynamics of heart rate and its neuro-humoral control in rainbow trout (Onchorhynchus mykiss L.) acclimating to 16 degrees C for 39 days after being acutely warmed from 9 degrees C. Resting heart rate was 39 beats min(-1) at 9 degrees C, and increased significantly when fish were acutely warmed to 16 degrees C (Q(10)=1.9), but then declined during acclimation (Q(10)=1.2 at day 39), mainly due to increased cholinergic inhibition while the intrinsic heart rate and adrenergic tone were little affected. Maximum heart rate also increased with warming, although a partial modest decrease occurred during the acclimation period. Consequently, heart rate scope exhibited a complex pattern with an initial increase with acute warming, followed by a steep decline and then a subsequent increase, which was primarily explained by cholinergic inhibition of resting heart rate.

Keywords

Acclimation dynamics; Cholinergic tone; Heart rate scope; Intrinsic heart rate; Maximum heart rate; Time course

Published in

Journal of Experimental Biology
2016, Volume: 219, number: 8, pages: 1106-1109

SLU Authors

• Gräns, Albin

  • Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Climate Research
Zoology


Publication identifier

DOI: https://doi.org/10.1242/jeb.134312

Permanent link to this page (URI)

https://res.slu.se/id/publ/80134