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Autonomic and behavioural thermoregulation in starved rats
Author(s) -
Sakurada Sotaro,
Shido Osamu,
Sugimoto Naotoshi,
Hiratsuka Yasuhiro,
Yoda Tamae,
Kanosue Kazuyuki
Publication year - 2000
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2000.00417.x
Subject(s) - starvation , thermogenesis , hypothermia , thermoregulation , medicine , endocrinology , chemistry , core temperature , biology , obesity
1 We investigated the mechanism of starvation‐induced hypothermia in rats. 2 Threshold core temperatures ( T cor ) for tail skin vasodilatation and cold‐induced thermogenesis were determined after a 3 day starvation using a chronically implanted intravenous thermode. Food deprivation significantly lowered the threshold T cor for heat production, but did not affect the heat loss threshold. 3 Thermogenic response to a fall in T cor below its threshold was enhanced by starvation. 4 Preferred ambient temperatures ( T pref ) and T cor were measured before and during a 3 day starvation in a thermal gradient. The 3 day starvation significantly lowered T cor only in the light phase of the day. The level of hypothermia was the same throughout the fasting period, while T pref gradually increased during the 3 days of starvation. 5 When rats were starved at a constant ambient temperature of 25°C (no thermal gradient), their T cor levels were comparable with those of the rats kept in the thermal gradient. 6 The results suggest that, in rats, hypothermia caused by starvation was not due to a decrement in thermogenic capability, but was due to a decrease in the threshold for the activation of thermogenesis.