|
|
||||||||
1 Departments of Psychology and Neuroscience, The Ohio State University, Columbus, Ohio 43210; and Departments of 2 Psychology and 3 Integrative Biology, University of California, Berkeley, California 94720
Golden-mantled ground squirrels (Spermophilus lateralis) undergo seasonal hibernation during which core body temperature (Tb) values are maintained 1-2°C above ambient temperature. Hibernation is not continuous. Squirrels arouse at ~7-day intervals, during which Tb increases to 37°C for ~16 h; thereafter, they return to hibernation and sustain low Tbs until the next arousal. Over the course of the hibernation season, arousals consume 60-80% of a squirrel's winter energy budget, but their functional significance is unknown and disputed. Host-defense mechanisms appear to be downregulated during the hibernation season and preclude normal immune responses. These experiments assessed immune function during hibernation and subsequent periodic arousals. The acute-phase response to bacterial lipopolysaccharide (LPS) was arrested during hibernation and fully restored on arousal to normothermia. LPS injection (ip) resulted in a 1-1.5°C fever in normothermic animals that was sustained for >8 h. LPS was without effect in hibernating squirrels, neither inducing fever nor provoking arousal, but a fever did develop several days later, when squirrels next aroused from hibernation; the duration of this arousal was increased sixfold above baseline values. Intracerebroventricular infusions of prostaglandin E2 provoked arousal from hibernation and induced fever, suggesting that neural signaling pathways that mediate febrile responses are functional during hibernation. Periodic arousals may activate a dormant immune system, which can then combat pathogens that may have been introduced immediately before or during hibernation.
circannual rhythms; Spermophilus lateralis; neural-immune interactions
This article has been cited by other articles:
![]() |
T. Ruf and W. Arnold Effects of polyunsaturated fatty acids on hibernation and torpor: a review and hypothesis Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R1044 - R1052. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P. Anisimov, S. V. Dentovskaya, G. M. Titareva, I. V. Bakhteeva, R. Z. Shaikhutdinova, S. V. Balakhonov, B. Lindner, N. A. Kocharova, S. N. Senchenkova, O. Holst, et al. Intraspecies and Temperature-Dependent Variations in Susceptibility of Yersinia pestis to the Bactericidal Action of Serum and to Polymyxin B Infect. Immun., November 1, 2005; 73(11): 7324 - 7331. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. F. Ruby, M. T. Barakat, and H. C. Heller Phenotypic Differences in Reentrainment Behavior and Sensitivity to Nighttime Light Pulses in Siberian Hamsters J Biol Rhythms, December 1, 2004; 19(6): 530 - 541. [Abstract] [PDF] |
||||
![]() |
K. L. Drew, M. B. Harris, J. C. LaManna, M. A. Smith, X. W. Zhu, and Y. L. Ma Hypoxia tolerance in mammalian heterotherms J. Exp. Biol., August 15, 2004; 207(18): 3155 - 3162. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. S. Kauffman, M. J. Paul, and I. Zucker Increased heat loss affects hibernation in golden-mantled ground squirrels Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2004; 287(1): R167 - R173. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. V. CAREY, M. T. ANDREWS, and S. L. MARTIN Mammalian Hibernation: Cellular and Molecular Responses to Depressed Metabolism and Low Temperature Physiol Rev, October 1, 2003; 83(4): 1153 - 1181. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Scholz Prostaglandins Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2003; 285(3): R512 - R514. [Full Text] [PDF] |
||||
![]() |
H. Scholz Fever Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2003; 284(4): R913 - R915. [Full Text] [PDF] |
||||
![]() |
G. F. DiBona Thermoregulation Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2003; 284(2): R277 - R279. [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |