Antagonism of the alpha receptor sub-type at gamma-aminobutyric acid (
GABA) recognition sites in developing pigs was evaluated using the GAB
A(A) receptor antagonist bicuculline. The effect of bicuculline infusi
ons was to produce an increase of phrenic and hypoglossal discharge am
plitudes. This bicuculline-induced effect on discharge amplitude was m
anifested in autopower spectra as an increase in the power of peaks lo
cated in the medium-frequency (10-50 Hz) band. More importantly, coher
ence estimates were increased by bicuculline administration demonstrat
ing GABA-mediated influences on a central pattern generator with outpu
t in the 10-50 Hz band.