It is important to understand how peripheral 5-HT affects urinary bladder function since drugs increasing 5-HT bioavailability (such as amitriptyline) were commonly prescribed for the treatment of voiding dysfunctions (Garba et al., 2022) and that serum 5-HT levels appear to be negatively correlated with symptoms of bladder overactivity (Okamoto et al., 2021). The gene discussed is HTR5A; the disease is overactive bladder.