Table 2.

Changes in cough-related variables recorded ~10 min following bilateral microinjections of 1 mM Bicuculline, 0.3 Muscimol, and vehicle solution into the cVRG.

	CN	TT, s	TI, s	TE, s	PPA, RU	PAA, RU
BICUCULLINE (n = 5)
Mechanical stimulation
Control	3.6 ± 0.24	0.52 ± 0.03	0.37 ± 0.02	0.15 ± 0.01	0.61 ± 0.04	0.57 ± 0.02
1 mM	4.4 ± 0.24*	0.49 ± 0.04	0.33 ± 0.04	0.15 ± 0.02	0.62 ± 0.06	0.59 ± 0.02
Citric acid inhalation
Control	5.0 ± 0.32	0.52 ± 0.01	0.33 ± 0.01	0.19 ± 0.01	0.63 ± 0.03	0.46 ± 0.02
1 mM	7.2 ± 0.37**	0.39 ± 0.01**	0.25 ± 0.01**	0.14 ± 0.02*	0.63 ± 0.02	0.61 ± 0.02**
MUSCIMOL (n = 5)
Mechanical stimulation
Control	3.8 ± 0.21	0.54 ± 0.02	0.36 ± 0.02	0.17 ± 0.01	0.64 ± 0.03	0.54 ± 0.02
0.3 mM	–	–	–	–	–	–
Citric acid inhalation
Control	5.2 ± 0.37	0.53 ± 0.02	0.35 ± 0.01	0.18 ± 0.01	0.60 ± 0.04	0.47 ± 0.02
0.3 mM	–	–	–	–	–	–
VEHICLE SOLUTION (n = 3)
Mechanical stimulation
Control	3.7 ± 0.33	0.51 ± 0.05	0.36 ± 0.04	0.15 ± 0.01	0.62 ± 0.04	0.56 ± 0.03
0.9% NaCl	3.6 ± 0.31	0.50 ± 0.05	0.37 ± 0.04	0.14 ± 0.01	0.63 ± 0.08	0.58 ± 0.02
Citric acid inhalation
Control	5.0 ± 0.58	0.51 ± 0.02	0.34 ± 0.02	0.17 ± 0.01	0.68 ± 0.02	0.46 ± 0.04
0.9% NaCl	5.2 ± 0.44	0.51 ± 0.01	0.35 ± 0.01	0.16 ± 0.01	0.67 ± 0.02	0.45 ± 0.03

Values are means ± SE; n, number of animals; cVRG, caudal ventral respiratory group; CN, cough number; T_T, cycle duration; T_I, inspiratory time; T_E, expiratory time; PPA, peak phrenic activity in relative units (RU); PAA, peak abdominal activity in relative units (RU); –, cough response absent or barely visible (non-measurable).

^*P < 0.05,

^**P < 0.005 compared with control coughs.