Anesthetic protocols for urodynamic studies of the lower urinary tract in small rodents-A systematic review

Urodynamic studies in rats and mice are broadly used to examine pathomechnisms of disease and identify and test therapeutic targets. This review aims to highlight the effects of the anesthetics on the lower urinary tract function and seeks to identify protocols that allow recovery from anesthesia and repeated measurements while preserving the function which is being studied. All studies published in English language, which compared the data obtained under various types of anesthesia and the urodynamics performed in awake animals were included. It appears that urethane, an anesthetic recommended extensively for the investigation of lower urinary tract function, is appropriate for acute urodynamic studies only. Major advantages of urethane are its stability and ability to preserve the micturition reflex. Due to its toxicity and carcinogenicity, urethane anesthesia should not be used for recovery procedures. This review evaluated available alternatives including propofol, isoflurane and combinations of urethane, ketamine/xylazine, ketamine/medetomidine, and/or fentanyl/fluanisone/midazolam. Different effects have been demonstrated among these drugs on the urinary bladder, the urethral sphincter, as well as on their neuroregulation. The lowest incidence of adverse effects was observed with the use of a combination of ketamine and xylazine. Although the variations in the reviewed study protocols represent a limitation, we believe that this summary will help in standardizing and optimizing future experiments.