We hypothesized that bilateral CDR (C3-C5) increases serotonergic innervation of phrenic motoneurons. Surgery on two rat groups (CDR and sham-operated; both N=6) was performed 28 days before sacrifice. Phrenic motoneurons labeled with cholera toxin B-fragment were reconstructed in three dimensions with a Neurolucida Imaging System. Serotonin immunoreactive terminals in immediate proximity to labeled phrenic motoneurons were counted, and terminal densities were calculated using estimates of soma (prolated sphere model) and dendrite (cylindrical model) surface areas based on measurements cell diameter. Absolute #'s Density (#/μ2) CDR Sham-operated CDR Sham-operated Soma 177 ± 10*132 ± 9 0.11 ± 0.01 0.12 ± 0.01 Dendrites 103 ± 20*70 ± 11 0.52 ± 0.08 0.49 ± 0.01*: vs. Sham-operated rats (p < 0.05). We conclude that CDR increases serotonergic innervation of the phrenic motor nucleus, maintaining terminal density despite enlarged motoneuron size (Zhan et al., ibid).
|Original language||English (US)|
|State||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology