Assessment of visceral sensitivity using radio telemetry in a rat model of maternal separation

• Published in: Neurogastroenterology and motility Vol. 17; no. 6; pp. 838 - 845
• Main Authors: Welting, O., Wijngaard, R. M., Jonge, W. J., Holman, R., Boeckxstaens, G. E.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.12.2005
• Subjects: Abdominal Muscles - physiology; Animals; Anxiety, Separation - psychology; Body Weight - physiology; Catheterization; colorectal distention; Electrodes, Implanted; Electromyography; Electrophysiology; Female; Handling (Psychology); irritable bowel syndrome; Maternal Deprivation; Muscle Contraction - physiology; radio telemetry; rat; Rats; Rats, Long-Evans; Rectum - physiology; stress; Stress, Psychological - physiopathology; Telemetry; visceral sensitivity
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/j.1365-2982.2005.00677.x

Stress plays an important role in the development of visceral hypersensitivity, a key mechanism underlying the pathophysiology of the irritable bowel syndrome. Visceral sensitivity in rats is generally assessed under restrain conditions. To avoid this potential stress factor, we developed a model using implanted radio telemetry for remote measurement of the visceromotor response (VMR) to colorectal distention (CRD). Ten days after implantation of a radio telemetry transmitter and EMG electrodes, visceral sensitivity was evaluated by applying a standardized distension protocol (1, 1.5 and 2 mL) on three different days. In a second series, visceral sensitivity was assessed in maternally separated rats before, directly after and at 6 and 24 h after water avoidance (WA) stress. CRD resulted in a reproducible VMR response on the three different study days. In separated but not in non‐handled rats, WA significantly increased visceral sensitivity at 6 h (P = 0.006) and 24 h (P = 0.004) after WA. Our results show that radio telemetry is a reliable and well tolerated new tool for evaluating visceral sensitivity in rats. These data further confirm that maternal separation is a good model for evaluating the mechanisms underlying visceral hypersensitivity.