Altered motor output to the ovipositor pulsatile organs by changing CO
concentrations in and around the terminal ganglion. (A) The isolated terminal ganglion (tg) shown with cut connectives (Conn) and cercal nerves (CN) and its supply with tracheal branches (T7v, T8v) originating from the main ventral trachea (Tmv) of the abdomen, one of which is cut and prepared for perfusion with air or an air/CO2 mixture (gas in/out). The large commissural trachea (Tcomm) is shown behind the tg. (B) Double recording (consecutive traces) of the nerves running to left and right anterior genital chamber muscles (7vA1 l/r) with temporal perfusion of 25% CO2 in air through left main tracheal trunk. (C) Continuous recording of 7vA1 bursting intervals while applying saline bubbled with a mixture of air and 50% CO2.The rhythm accelerates and later deteriorates. (D) Average burst durations of rhythmic bursts in nerve 7vA1 during bath application of different pH levels of saline. Frequencies rise (burst duration decrease) with higher acidity due to HCl or 25% CO2 diluted in saline. Action potential amplitudes decrease with higher salinity.