Absence of the cholecystokinin-A receptor deteriorates homeostasis of body temperature in response to changes in ambient temperature.
The circadian rhythm of the body core temperature (T(c)) and the effects of changes in ambient temperatures on the homeostasis of T(c) in Otsuka Long Evans Tokushima Fatty (OLETF) rats, which are naturally occurring cholecystokinin (CCK)-A receptor (CCK-AR) gene knockout (-/-) rats, were examined. In addition, the peripheral responses to warming or cooling of the preoptic and anterior hypothalamic region (PO/AH) were determined. The circadian rhythm of T(c) in OLETF rats was similar to that in Long-Evans Tokushima (LETO) rats; this rhythm was characterized by a higher T(c) during the dark period and a lower T(c) during the light period. When the ambient temperature was changed within the limits of 0 degrees C to 30 degrees C, the changes in T(c) of LETO rats were associated with the changes in ambient temperature, whereas those in OLETF rats were dissociated from the temperature changes. The OLETF rats showed a large hysteresis. The peripheral responses to warming or cooling of PO/AH, including shivering of the neck muscle and changes in skin temperature of the tail and footpad, were similar in OLETF and LETO rats. To confirm the role of CCK-AR in the regulation of body temperature, the values of T(c) in the CCK-AR(-/-) mice were compared with those in CCK-B receptor (CCK-BR) (-/-), CCK-AR(-/-)BR(-/-), and wild-type mice. In the mice, the circadian rhythms of T(c) were the same, regardless of the genotype. Mice without CCK-AR showed larger hysteresis than mice with CCK-AR. From these results, we conclude that the lack of CCK-AR causes homeostasis of T(c) in rats and mice to deteriorate.
Nomoto
Shigeki
S
Department of Clinical Physiology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashiku Tokyo 173-0015, Japan.
Ohta
Minoru
M
Kanai
Setsuko
S
Yoshida
Yuki
Y
Takiguchi
Soichi
S
Funakoshi
Akihiro
A
Miyasaka
Kyoko
K
D000818:Animals; D030801:Animals, Genetically Modified; D001831:Body Temperature / Q000502:physiology*; D002940:Circadian Rhythm; D003080:Cold Temperature; D005838:Genotype; D006706:Homeostasis / Q000502:physiology*; D006358:Hot Temperature; D007032:Hypothalamus, Anterior / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011301:Preoptic Area / Q000378:metabolism; D051381:Rats; D020334:Rats, Inbred OLETF; D011922:Rats, Mutant Strains; D043886:Receptor, Cholecystokinin A / Q000502:physiology*; D043887:Receptor, Cholecystokinin B / Q000502:physiology; D013696:Temperature
D043886:Receptor, Cholecystokinin A; D043887:Receptor, Cholecystokinin B