title: Behavioral hypothermia of a domesticated lizard under treatment of the hypometabolic agent 3-iodothyronamine.
abstract: Ectothermic animals rely on behavioral thermoregulation due to low capacity of heat production and storage. Previously, lizards were shown to achieve 'fever' during microbial infection by increasing their preferred body temperature (PBT) behaviorally, thereby attaining a relatively high survival rate. The purpose of this study was to investigate whether domesticated lizards pursued 'behavioral hypothermia' induced by a hypometabolic agent 3-iodothyronamine (T1AM). We found that treatment with 8.0 mg/kg T1AM caused a lizard species, the leopard gecko (Eublepharis macularius), to decrease its ventilation and oxygen consumption rates 0.64- and 0.76-fold, respectively, compared to those of the control (P<0.05). The lizards, habituated at an ambient temperature of 30 ± 0.5°C, also showed a significant decrease in the PBT range over a freely accessible thermal gradient between 5°C and 45°C. The upper limit of the PBT in the treated lizards lowered from 31.9°C to 30.6°C, and the lower limit from 29.5°C to 26.3°C (P<0.001). These findings demonstrate that the treated lizards pursued behavioral hypothermia in conjunction with hypoventilation and hypometabolism. Because prior studies reported a similar hypometabolic response in T1AM-injected laboratory mice, the domesticated lizards, as a part of the vertebrate phylogeny, may be a useful laboratory model for biological and pharmacological researches such as drug potency test.
authors: Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju, Gangwon-do, 26493, Republic of Korea.
authors: Kyoungbong
authors: K
authors: Ha
authors: Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju, Gangwon-do, 26493, Republic of Korea.
authors: Haksup
authors: H
authors: Shin
authors: Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju, Gangwon-do, 26493, Republic of Korea.
authors: Hyunwoo
authors: H
authors: Ju
authors: Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Wonju, Gangwon-do, 26493 Republic of Korea.
authors: Chan-Moon
authors: CM
authors: Chung
authors: Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Wonju, Gangwon-do, 26493, Republic of Korea.
authors: Inho
authors: I
authors: Choi
mesh_terms: D000818:Animals; D000829:Animals, Domestic; D001522:Behavior, Animal / Q000502:physiology*; D001833:Body Temperature Regulation / Q000187:drug effects* / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects; D007035:Hypothermia; D008116:Lizards / Q000378:metabolism* / Q000502:physiology*; D051379:Mice; D010101:Oxygen Consumption / Q000187:drug effects; D013696:Temperature; D013970:Thyronines / Q000494:pharmacology*
chemical_list: C487948:3-iodothyronamine; D013970:Thyronines
keywords: 3-Iodothyronamine; behavioral hypothermia; lizards; metabolism; thermoregulation