title: Involvement of opioid receptors in inhibition of bladder overactivity induced by sacral neuromodulation in pigs: A possible action mechanism.
abstract: OBJECTIVE
  To determine the role of opioid receptors in the inhibition of bladder overactivity by sacral neuromodulation (SNM) in pigs, and explore the possible mechanism of SNM.
  
  
  METHODS
  Both implant-driven stimulators of the S3 spinal nerve were implanted in seven pigs. Naloxone and tramadol were administered. Multiple cystometrograms were performed to determine the effects of SNM and opioid receptors on the micturition reflex by infusing normal saline (NS) or acetic acid (AA).
  
  
  RESULTS
  AA-induced bladder overactivity significantly reduced the bladder capacity (BC) to 29.9 ± 3.9% of the NS control level (413.1 ± 55.4 mL) (P < 0.01). SNM significantly increased the BC to 39.4 ± 5.5% of the NS control level (P < 0.03). In the absence of SNM, the cumulative dose of naloxone (0.02 and 0.2 mg/kg intravenously) did not significantly change the BC (25.1 ± 3.1% and 20.2 ± 3.1% of the NS control level, respectively) (P > 0.05). In the presence of SNM, both doses of naloxone significantly reduced the BC to 27.2 ± 3.0% and 25.1 ± 2.9% of the NS control level (P < 0.05), respectively. In the absence of SNM, tramadol did not significantly change the BC (31.5 ± 3.9% of the NS control level) (P > 0.05). In the presence of SNM, tramadol significantly increased the BC to 49.1 ± 6.1% of the NS control level (P < 0.01).
  
  
  CONCLUSIONS
  Opioid receptors play a role in inhibition of bladder overactivity during SNM. Combining SNM with tramadol could be a novel treatment modality for overactive bladder.
authors.affiliation: Rehabilitation School of Capital Medical University, Beijing, China.|Department of Urology, China Rehabilitation Research Centre, Beijing, China.|Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China.|Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.affiliation: Rehabilitation School of Capital Medical University, Beijing, China.|Department of Urology, China Rehabilitation Research Centre, Beijing, China.|Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China.|Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.
authors.forename: Limin
authors.initials: L
authors.lastname: Liao
authors.affiliation: Rehabilitation School of Capital Medical University, Beijing, China.|Department of Urology, China Rehabilitation Research Centre, Beijing, China.|Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China.|Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Chen
authors.affiliation: Rehabilitation School of Capital Medical University, Beijing, China.|Department of Urology, China Rehabilitation Research Centre, Beijing, China.|Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China.|Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Rehabilitation School of Capital Medical University, Beijing, China.|Department of Urology, China Rehabilitation Research Centre, Beijing, China.|Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China.|Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China.
authors.forename: Han
authors.initials: H
authors.lastname: Deng
mesh_terms: D019342:Acetic Acid; D000818:Animals; D005260:Female; D008297:Male; D009270:Naloxone / Q000494:pharmacology* / Q000627:therapeutic use; D012018:Reflex / Q000187:drug effects; D012447:Sacrum; D013127:Spinal Nerves / Q000187:drug effects*; D013552:Swine; D014147:Tramadol / Q000494:pharmacology*; D004561:Transcutaneous Electric Nerve Stimulation; D053201:Urinary Bladder, Overactive / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*; D014554:Urination / Q000187:drug effects / Q000502:physiology*
chemical_list: D009270:Naloxone; D014147:Tramadol; D019342:Acetic Acid
keywords: naloxone; neurotransmitter; opioid receptor; sacral neuromodulation; tramadol