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Following histamine perfusion onto Syrian hamster hippocampal slices, enhanced neural excitability was observed on a pathway projecting to the brainstem
Author(s) -
Nguyen Yen Ha,
Horowitz John M,
Hamilton Jock S.,
Horwitz Barbara A.
Publication year - 2009
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.23.1_supplement.778.12
Subject(s) - hippocampal formation , histamine , brainstem , neuroscience , stimulation , hippocampus , population , population spike , medicine , reticular formation , endocrinology , chemistry , biology , dentate gyrus , environmental health
Previous studies suggest that signals from the hippocampus control the duration of a bout of hibernation. Specifically, histamine injected into the whole hippocampus lengthened each hibernation bout (Sallmen, et al., Brain Res. 2003, 966:317‐20). However, neural activity of the population of CA3 hippocampal neurons that project to the brainstem reticular activating system (RAS) has not been studied. We tested the hypothesis that histamine modulates CA3 region excitability. Using hippocampal slices from euthermic and hibernating Syrian hamsters, evoked responses were recorded before, during, and after histamine perfusion at 30 o C. Histamine increased the slope of the second peak of the evoked response from ‐0.0366 + 0.010 to ‐0.0631 + 0.008, a 72.4% increase (P < 0.05, 7 slices from 5 hamsters). Thus, in the presence of histamine, stimulation of the dentate granule cell axons elicited an enhanced oscillatory response in CA3 pyramidal cell axons projecting to the brainstem. These data are consistent with the hypothesis that histamine augments signals to brainstem RAS neurons and thus may prolong the duration of a hibernation bout. This study was supported by an UC Davis President's Undergraduate Fellowship award to YHN.