title: Hyperosmolality in the plasma modulates behavioral thermoregulation in mice: the quantitative and multilateral assessment using a new experimental system.
abstract: We evaluated the effect of plasma hyperosmolality on behavioral thermoregulation in mice, using a new experimental system. The system consisted of Plexiglas box (dimensions: 50×12×19 cm) with five computer-controlled Peltier boards (dimensions: 10×10 cm) at the bottom. Experiments were conducted in two different settings of the system. An operant behavior setting: each board was first set to 39°C, and the right-end board was changed to 20°C for 1 min when a mouse moved to a specific position. A temperature mosaic setting: each board was randomly set to 15°C, 22°C, 28°C, 35°C, or 39°C with a 6-min interval, but each board temperature was different from the others at a given time point. Mice were injected subcutaneous (s.c.) isotonic or hypertonic saline (154 mM (IS group) or 2,500 mM (HS group), 10 ml/kg body wt), and exposed to either setting for 90 min. In the operant setting, the HS group showed fewer operant behavior counts than the IS group (11±5 and 25±4 counts, respectively; P<0.05) with greater increase in body temperature (1.6±0.4°C vs. 0.0±0.2°C, respectively; P<0.05). In the mosaic setting, the HS group selected the board temperature of 35°C more frequently than the other temperatures (P<0.05) with the same increase in body temperature. These results may suggest that plasma hyperosmolality modulates behavioral thermoregulatory response to heat and induce regulated hyperthermia.
authors.affiliation: Sport Sciences for the Promotion of Active Life, Japan.
authors.forename: Cheng-Hsien
authors.initials: CH
authors.lastname: Lin
authors.forename: Ken
authors.initials: K
authors.lastname: Tokizawa
authors.forename: Mayumi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Yuki
authors.initials: Y
authors.lastname: Uchida
authors.forename: Hisae
authors.initials: H
authors.lastname: Mori
authors.forename: Kei
authors.initials: K
authors.lastname: Nagashima
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D001831:Body Temperature / Q000187:drug effects / Q000502:physiology*; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology*; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D002755:Choice Behavior / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects; D006979:Hyperthermia, Induced / Q000379:methods; D007036:Hypothermia, Induced / Q000379:methods; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009994:Osmolar Concentration; D010949:Plasma / Q000187:drug effects / Q000378:metabolism*; D015203:Reproducibility of Results; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
chemical_list: D012462:Saline Solution, Hypertonic