The vesicular acetylcholine transporter (VAChT) RNA showed the greatest variability (SD = 0.89), whilst the level of the neuronal nitric oxide synthase (nNOS) transcript, which has a role in protection against cardiac arrhythmia [37,38], was the most consistent between individual mice (SD = 0.10). Here, SLC18A3 is linked to chronic obstructive pulmonary disease.