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Titolo:
Does behavioural hypothermia promote post-exercise recovery in cold-submerged frogs?
Autore:
Tattersall, GJ; Boutilier, RG;
Indirizzi:
Univ Cambridge, Dept Zool, Cambridge CB2 3EJ, England Univ Cambridge Cambridge England CB2 3EJ ool, Cambridge CB2 3EJ, England
Titolo Testata:
JOURNAL OF EXPERIMENTAL BIOLOGY
fascicolo: 5, volume: 202, anno: 1999,
pagine: 609 - 622
SICI:
0022-0949(199903)202:5<609:DBHPPR>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
RANA-CATESBEIANA; METABOLIC RECOVERY; ANURAN AMPHIBIANS; MAXIMAL OXYGEN; BUFO-MARINUS; BODY SIZE; TEMPERATURE; HYPOXIA; MECHANISMS; BULLFROGS;
Keywords:
behavioural hypothermia; temperature selection; thermoregulation; overwintering; amphibian; exhaustive exercise; recovery; frog; Rana temporaria;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
56
Recensione:
Indirizzi per estratti:
Indirizzo: Tattersall, GJ NE Ohio Univ, Coll Med, Dept Physiol, Rootstown, OH 44272 USA NE Ohio Univ Rootstown OH USA 44272 ootstown, OH 44272 USA
Citazione:
G.J. Tattersall e R.G. Boutilier, "Does behavioural hypothermia promote post-exercise recovery in cold-submerged frogs?", J EXP BIOL, 202(5), 1999, pp. 609-622

Abstract

At the low temperatures of the overwintering environment of the frog Rana temporaria, small changes in ambient temperature have large effects on metabolism and behaviour, especially since Q(10) values are often greatly elevated in the cold. How the overwintering aquatic frog copes with variable thermal environments in terms of its overall activity metabolism and recovery from pursuit by predators is poorly understood, as is the role of behavioural thermoregulation in furthering recovery from intense activity, Exhaustive exercise was chosen as the method of evaluating activity capacity (defined by time to exhaustion, total distance swum and number of leg contractionsbefore exhaustion) and was determined at 1.5 and 7 degrees C, Other cohorts of frogs were examined at both temperatures to determine the metabolic (acid-base, lactate, glucose, ATF and creatine phosphate) and respiratory responses to exercise in cold-submerged frogs. Finally, temperature preferencebefore and after exercise was determined in a thermal gradient to define the importance of behavioural thermoregulation on the recovery rates of relevant metabolic and respiratory processes. Activity capacity was significantly reduced in frogs exercised at 1.5 versus 7 degrees C, although similar levels of tissue acid-base metabolites and lactate were reached, Blood pH, plasma PCO2 and lactate levels recovered more rapidly at 1.5 degrees C than at 7 degrees C; however, intracellular pH and the recovery of tissue metabolite levels were independent of temperature. Resting aerobic metabolic rates were strongly affected by temperature (Q(10)=3.82); however, rates determined immediately after exercise showed a reduced temperature sensitivity (Q(10)=1.67) and, therefore, a reduced factorial aerobic scope, Excess oxygenconsumption recovered to resting values after 5-6.25 h, and 67% recovery times tended to be slightly faster at the lower temperatures, Exercise in the cold, therefore, provided an immediately higher factorial scope, which could be involved in the faster rate of recovery of blood lactate levels in the colder frogs, In addition, exercise significantly lowered the preferred temperature of the frogs from 6.7 to 3.6 degrees C for nearly 7 h, after which they returned to their normal, unstressed preferred temperatures. Thus,a transient behavioural hypothermia in the skin-breathing, overwintering frog may be an important strategy for minimising post-exercise stress and maintaining aerobic metabolism during recovery from intense activity.

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Documento generato il 15/07/20 alle ore 15:04:44