Peripheral or central administration of NE 52-QQ57 has no effect on CO2-induced respiratory responses.
A. Averaged responses (left) and raw traces (right) to illustrate responses to hypercapnia after i.p. administration of NE 52-QQ57 (20 mg kg−1). Di – raw activity of the diaphragm, ʃDi – integrated activity of the diaphragm to illustrate respiration.
B. Effect of i.p. administration of NE 52-QQ57 (20 mg kg−1) on baseline diaphragmatic EMG activity.
C. Responses to hypercapnia after topical application of NE 52-QQ57 (1mM) on the ventral surface of the medulla oblongata. NE 52-QQ57 had no effect on CO2-induced responses (two-way ANOVA). PN – activity of the phrenic nerve.
D. Effect of direct application of NE 52-QQ57 (1mM) on the ventral surface of the medulla oblongata on baseline phrenic nerve activity. PN Rate – frequency of respiration measured from the ʃPN traces.