Investigating the Pharmacological Impact of Atosiban, an Oxytocin Receptor Antagonist, on Bladder and Prostate Contractions Within OBESE and Non-Obese Rats

<b>Background/Objectives:</b> Lower urinary tract symptoms (LUTS), such as frequency, urgency, nocturia, and urge incontinence, are commonly linked to overactive bladder (OAB) and benign prostatic hyperplasia (BPH). Oxytocin receptor (OXTR) upregulation has been proposed to enhance bladder and prostate contractility, while obesity is a recognized risk factor for LUTS, OAB, and BPH. This study aimed to investigate whether the OXTR antagonist atosiban attenuates spontaneous and oxytocin-induced contractions in bladder and prostate tissues from obese and non-obese rats. <b>Methods:</b> Bladder and prostate tissues were obtained from obese and non-obese rats and studied in in vitro organ bath preparations. The effects of atosiban (1 µM and 10 µM) on spontaneous contractility and oxytocin-induced responses were examined. Immunohistochemistry was performed to evaluate OXTR expression in the bladder. <b>Results:</b> Atosiban significantly reduced spontaneous contractions in the bladder (<i>p</i> < 0.0001 in obese; <i>p</i> < 0.01 in non-obese) and prostate (<i>p</i> < 0.01 in obese; <i>p</i> < 0.0001 in non-obese). Oxytocin-induced bladder contractions were significantly increased in obese rats but were attenuated by atosiban at 10 µM (<i>p</i> < 0.05), an effect absent in non-obese rats. Immunohistochemical analysis confirmed elevated OXTR expression in both epithelial and stromal compartments of the bladder in obese rats (<i>p</i> < 0.05). <b>Conclusions:</b> These findings indicate that oxytocin contributes to bladder and prostate hypercontractility, particularly in obesity. Targeting OXTR with atosiban may represent a novel therapeutic strategy for the management of LUTS, OAB, and BPH.