Circannual control of hibernation by HP complex in the brain.
Seasonal hibernation in mammals is under a unique adaptation system that protects organisms from various harmful events, such as lowering of body temperature (Tb), during hibernation. However, the precise factors controlling hibernation remain unknown. We have previously demonstrated a decrease in hibernation-specific protein (HP) complex in the blood of chipmunks during hibernation. Here, HP is identified as a candidate hormone for hibernation. In chipmunks kept in constant cold and darkness, HP is regulated by an individual free-running circannual rhythm that correlates with hibernation. The level of HP complex in the brain increases coincident with the onset of hibernation. Such HP regulation proceeds independently of Tb changes in constant warmth, and Tb decreases only when brain HP is increased in the cold. Blocking brain HP activity using an antibody decreases the duration of hibernation. We suggest that HP, a target of endogenously generated circannual rhythm, carries hormonal signals essential for hibernation to the brain.
Kondo
Noriaki
N
Mitsubishi Kagaku Institute of Life Sciences, Machida, Tokyo 194-8511, Japan. nkondo@libra.ls.m-kagaku.co.jp
Sekijima
Tsuneo
T
Kondo
Jun
J
Takamatsu
Nobuhiko
N
Tohya
Kazuo
K
Ohtsu
Takashi
T
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D001798:Blood Proteins / Q000134:cerebrospinal fluid / Q000235:genetics / Q000378:metabolism*; D001831:Body Temperature / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism* / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D003080:Cold Temperature; D005786:Gene Expression Regulation; D006605:Hibernation / Q000502:physiology*; D008099:Liver / Q000378:metabolism; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000134:cerebrospinal fluid / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D012589:Sciuridae / Q000378:metabolism; D013997:Time Factors
D000906:Antibodies; D001798:Blood Proteins; C081698:HP-20 protein, Tamias asiaticus; D046912:Multiprotein Complexes