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Neural control of cardiorespiratory function in ground squirrels during hibernation.
Author(s) -
Hengen Keith B.,
Johnson Stephen M.,
Carey Hannah V.,
Behan Mary
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1401
Subject(s) - hibernation (computing) , cardiorespiratory fitness , ground squirrel , neuroscience , medicine , biology , computer science , state (computer science) , algorithm , squirrel monkey
Torpor and hibernation are among the most extreme examples of energy conservation and CNS plasticity in endotherms. During torpor in 13‐lined ground squirrels ( Spermophilus tridecemlineatus ), respiratory rate decreases 98% and heart rate drops to ~ 1% of the aroused state. Despite the overall suppression of neuronal activity during torpor, cardiorespiratory function is carefully maintained and restored to normal levels during interbout arousals (IBA). Little is known of the central mechanisms that regulate autonomic function in hibernators. Thus, we are investigating neuronal populations in the brainstem that control cardiorespiratory function across the hibernation cycle. We used immunocytochemical detection of FOS, a marker of neuronal activity to identify and neurochemically characterize cardiorespiratory control centers in brainstem from summer squirrels and in specific hibernation states. Preliminary results indicate greater FOS activity in caudal raphe of torpid vs. summer squirrels; FOS was expressed in parabrachial nuclei in IBA squirrels, and some FOS‐positive neurons in hibernators expressed 5‐HT immunoreactivity. We speculate that cardiorespiratory nuclei remain active during torpor and demonstrate state‐associated changes in neuronal activity patterns as animals cycle into and out of torpor. Supported by DARPA W81XWH05020016 (HC), NIH AG18760 (MB).