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Focal acidosis in the pre‐Botzinger complex of the awake goat increases respiratory frequency
Author(s) -
Krause K L,
Davis S,
Bonis J M,
Pan L,
Qian B,
Forster H V
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.a919
Subject(s) - tidal volume , anesthesia , respiratory acidosis , respiratory system , fastigial nucleus , medulla oblongata , fourth ventricle , acidosis , chemistry , medicine , anatomy , central nervous system , stimulation
Dialyzing mock cerebral spinal fluid (mCSF) equilibrated with 25% CO 2 in the retrotrapezoid nucleus and the nucleus of the solitary tract of the awake rat increased inspiratory flow (V I ) and tidal volume (V T ) by 24 and 11%. In the awake goat, we found that dialyzing 25 and 80% CO2 at one site in the raphe increased V I and V T 8–10%, while dialyzing 50% in the rostral part of the cerebellar fastigial nucleus increased V I and V T 14–16%. The pre‐Botzinger complex (PBC), a hypothesized respiratory rhythm generator, increased phrenic nerve activity after an acetazolamide‐induced acidosis in the anesthetized cat. Thus, we tested the hypothesis that focal microdialysis (MD) of CO 2 /H + in the PBC during wakfulness would stimulate breathing. Stainless steel microtubules were bilaterally implanted into the PBC of adult goats. Unilateral MD of mCSF equilibrated with 6.4% CO 2 did not affect V I , V T or f. Unilateral MD of 25 or 50% CO 2 did not affect V I or V T , but did significantly increase f by a maximum of 10% (P<0.05, n=12). Bilateral MD of 6.4 and 25% CO 2 did not significantly affect V I , V T , or f. However, bilateral MD of 50% significantly increased f by a maximum of 8% (n<0.05, n=5), although V I and V T was unaffected. The findings that FA in the PBC of the awake goat affects only respiratory frequency lends support to the PBC’s role in respiratory rhythm generation. Thus, our data suggests that the PBC may not only be instrinsically rhythmogenic, but chemosensitive as well. (Supported by NIH 25739 and the Veterans Administration)