Intracavernous Pressure Change During Penile Erection in the Rat

Three researchers from Paris, France have pioneered a method to monitor pressure in the corpora cavernosa of unrestrained rats during copulatory behaviors. Drs. Francois Giuiliano, Jacques Bernabe, and Olivier Rampin have been working together for the last four years to try to better understand the neurophysiology of penile erection.

Dr. Giuiliano, a surgeon and urologist, Dr. Bernabe and Dr. Rampin, both research scientists, met four years ago during their post-doctoral studies. Drs. Giuiliano and Bernabe believed that by studying the physiology of penile erection they would be able to better understand the neural controls responsible. At that time, methods to monitor pressure or electrophysiology in the freely moving rat were not easily available. There was disagreement between the researchers of the feasibility of monitoring these values. The result of this disagreement was a bet, and the three decided to pursue the task of developing a functional model to study these pmeters.

The group began their work using an anesthetized model and a fluid-filled catheter attached to a pressure transducer. Using this method the potential value of their model became apparent. The final challenge however, was to find a way to collect this data in an awake, freely moving animal model. With the cooperation of Phymep, a DSI distributor at that time, the group was able to work with the DSI telemetry research system on loan until they verified the feasibility of the system. Following 12 years of trial and error, they finally succeeded in developing a technique which allowed them to chronically place a catheter into the corpora cavernosa in an adult rat. At 9:00 PM one evening, after many disappointments, Dr. Giuliano and Dr. Rampin called Dr. Bernabe to tell him to 'get in here, it is working!' They were collecting pressure data. The group used a TA11PA-C40 pressure and activity transmitter with a modified 3mm thin-walled tip. Using an analog converter, they collected data on a strip chart recorder. They also video-taped the animals to allow visual verification of behaviors.

The group has published several papers on their technique and findings. Recently they were given an award at the Sixth World Meeting on Impotence September 1994 in Singapore for the best poster presentation of the meeting for their poster titled Telemetric Monitoring of Episodic Spontaneous Increases in Intracavernous Pressure in the Rat Over 24-Hour Periods.

Drs.Giuliano, Bernabe and Rampin look forward to continuing to improve their model and advance their data analysis techniques. By using their model, they hope to better understand the neural control of erections. This model should be a very interesting tool for the pharmacological approach to the oral treatment of impotence. In fact, this model would allow researchers to reliably measure penile erection in various situations in the freely moving rat. This understanding will aid in the treatment of individuals who may have experienced nerve injury, diabetes or other causes of impotence.

Telemetric Monitoring of Intracavernous Pressure in Freely Moving Rats During Copulation Giuliano, F. Bernabe, J. Rampin, O. Courtois, F. Benoit, G. Rousseau, J. The Journal of Urology 1994 1271-1274

Intracavernous Pressure Changes During Reflexive Penile Erections in the Rat Bernabe, J. Rampin, O. Giuliano, F. Benoit, G. The Journal of Urology 1995 57

Physiological Evidence of Neural Pathways Involved in Relfexogenic Penile Erection in the Rat Rampin, O. Giuliano, F. Dompeyre, P. Rousseau, J. Neuroscience Letters 1994 138-142

Telemetric Monitoring of Episodic Spontaneous Increases in Intracavernous Pressure in the Rat Over 24-Hour Periods Bernabe, J. Giuliano, F. Rampin, O. Sachs, B.D. International Journal of Impotence Research 1994 19