Temperature acclimation alters cardiac performance in the lobster Homarus americanus

Abstract

The American lobster is a poikilotherm that inhabits a marine environment where temperature varies over a 25 degrees C range and depends on the winds, the tides and the seasons. To determine how cardiac performance depends on the water temperature to which the lobsters are acclimated we measured lobster heart rates in vivo. The upper limit for cardiac function in lobsters acclimated to 20 degrees C is approximately 29 degrees C, 5 degrees C warmer than that measured in lobsters acclimated to 4 degrees C. Warm acclimation also slows the lobster heart rate within the temperature range from 4 to 12 degrees C. Both effects are apparent after relatively short periods of warm acclimation (3-14 days). However, warm acclimation impairs cardiac function at cold temperatures: following several hours exposure to frigid (<5 degrees C) temperatures heart rates become slow and arrhythmic in warm acclimated, but not cold acclimated, lobsters. Thus, acclimation temperature determines the thermal limits for cardiac function at both extremes of the 25 degrees C temperature range lobsters inhabit in the wild. These observations suggest that regulation of cardiac thermal tolerance by the prevailing environmental temperature protects against the possibility of cardiac failure due to thermal stress.

Master of all trades: thermal acclimation and adaptation of cardiac function in a broadly distributed marine invasive species, the European green crab,Carcinus maenas

“…1C). A similar effect of acclimation on lowtemperature heart rate has been reported in lobsters (Camacho et al, 2006), mussels of the genus Mytilus (Braby and Somero, 2006) and snails of the genus Chlorostoma (formerly the genus Tegula) (Stenseng et al, 2005). Studies in fishes also have shown that lowtemperature acclimation results in a broad suite of cardiac changes including enhanced ability to sustain function at low temperatures (Jayasundara and Somero, 2013), increased heart mass (Vornanen et al, 2005), and up-regulation of genes involved in protein synthesis and transcriptional regulation (Gracey et al, 2004).…”

“…This is slightly less than the maximum acclimation ability in cardiac thermal tolerance seen for the low intertidal porcelain crabs P. eriomerus and P. manimaculis (2.1 and 3.5°C, respectively), which had the highest acclimation ability of six congeneric species studied (Stillman, 2004). Lobsters were also quite plastic, with a 3°C increase in heat tolerance between 4 and 20°C acclimation (Camacho et al, 2006). While C. maenas was less plastic than these species, it maintains a considerably higher constitutive heat tolerance (Fig.…”

“…Such reductions in cardiac function at high temperatures lead to an inability to maintain aerobic scope, and thus represent a loss of key behavioral abilities such as the locomotory capacity needed in predator-prey interactions (Pörtner, 2002;Casselman et al, 2012). Cardiac limits can be shifted in response to short-term acclimation in some species (Stillman, 2003;Stenseng et al, 2005;Camacho et al, 2006), and have been shown to reflect long-term environmental adaptation to differences in habitat temperature due to latitude or altitude, e.g. to vertical position in intertidal habitats (Stillman, 2002;Stenseng et al, 2005;Eliason et al, 2011).…”

The cardiac response of the crabChasmagnathus granulatusas an index of sensory perception

“…In decapod crustaceans many studies have used the changes in a vegetative index to monitor the effects of a wide range of environmental variables on the physiology: water currents (Larimer, 1964), P O2 (Airriess and McMahon, 1994), ammonia (NH 3 ) (Bloxham et al, 1999), heavy metals (Aagaard et al, 2000), ambient CO 2 /O 2 (Gannon and Henry, 2004), water temperature (Camacho et al, 2006). In addition, the responses to several types of stimuli (tactile and chemical cues) were examined for their effects on the heart and ventilatory rate of crayfish, finding a reflex inhibition in the majority of them (Larimer, 1964).…”

Multiple modulators act on the cardiac ganglion of the crab,Cancer borealis

“…Such manipulations make it difficult to compare the actions of different substances on CG motor output. For example, recent studies using the isolated heart preparation have shown that cardiac performance in the lobster, Homarus americanus, is temperature-dependent (Camacho et al, 2006;Worden et al, 2006). Secondly, studies on the isolated CG have been done using many different species, which poses the question of whether the effect of a single modulator in one Neuromodulators can change the output of neural circuits.…”