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Developmental effects of ketamine on inspiratory hypoglossal nerve activity studied in vivo and in vitro
Author(s) -
Berger Albert Jeffrey,
Sebe Joy
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.21.5.a558-c
Subject(s) - ketamine , hypoglossal nerve , in vivo , rhythm , inhibitory postsynaptic potential , neuroscience , chemistry , biology , medicine , tongue , pathology , microbiology and biotechnology
The effects of ketamine on properties of mouse hypoglossal nerve inspiratory bursts (I‐bursts) were studied in vivo and in vitro. In spontaneously breathing urethane anesthetized mice we observed rhythmic hypoglossal I‐phase activity in only 1 of 8 P9 pups. In contrast in older mice (≥ P10) rhythmic I‐phase activity was almost always observed. Ketamine caused a reduction in I‐burst frequency and an increase in peak integrated hypoglossal nerve activity in all three age groups studied (P10–P13, P15–P20 and adult mice). In these mice I‐phase synchronous oscillations were observed in control and after ketamine. Synchronous oscillations occur when inspiratory motoneurons fire clusters of action potentials at a particular frequency during an I‐burst. Ketamine did not change the frequency of the dominant spectral peak arising from these synchronous oscillations. The effects of ketamine were also studied in the mouse rhythmic medullary slice preparation. Ketamine reduced both hypoglossal I‐burst frequency and I‐burst peak integrated amplitude. As in the in vivo studies ketamine did not shift the dominant spectral peak frequency of the synchronous oscillations. These results demonstrate that in vivo and in vitro ketamine results in significant changes in long‐time‐scale I‐phase properties, but changes in the short‐time‐scale properties (synchronous oscillations) are minimal. Supported by NIH grant HL‐49657.