Temperature dependence of cardiac performance in the lobsterHomarus americanus

• DOI: 10.1242/jeb.02082
• Publication Date: 2006-03-02T20:03:05Z
• Authors: Mary Kate Worden; Christine M. Clark; Mark Conaway; Syed Aman Qadri
• Keywords: Heart beat; American lobster; Q10; Atmospheric temperature range

SUMMARY The lobster Homarus americanus inhabits ocean waters that vary in temperature over a 25°C range, depending on the season and water depth. To investigate whether heart functions effectively wide range of temperatures we examine dependence cardiac performance isolated hearts vitro. In addition, examined modulation by serotonin depends temperature. strength heartbeat strongly temperature, as are warmed from 2 to 22°C contraction amplitude decreases greater than 60%. rates relaxation most dependent 4°C but become independent at warmer temperatures. Heart increase function both intact animals, however animals beat faster 12–20°C. Interestingly, acute Q10 values for rate similar vivo vitro suggesting arises mainly effects ganglion. contrast earlier reports frequency positively correlated, observe no consistent relationship between these parameters they change Stroke volume However, opposing temperature-dependent partially compensates produce output which is maximal 10°C significantly above 20°C. Serotonin potentiates temperature-independent manner. Overall, our results show although underlying different patterns dependence, remains relatively constant environmental wild.