A conscious-rabbit model for the long-term observation of urethral and arterial pressures.
OBJECTIVE
To describe and evaluate a new experimental model for the simultaneous measurement of urethral (UP) and arterial (AP) pressures in the conscious rabbit, thereby avoiding the interference of anaesthesia which markedly reduces reflex activity and tone of smooth muscle.


METHODS
Female rabbits were anaesthetized and catheters inserted into the urethra, abdominal aorta, jugular vein and bladder. After recovering from surgery, rabbits were trained to remain static in a sling for a period of 2 h, during which the UP and AP were recorded. The model was validated for short- and long-term stability before the effects of drugs were assessed; UP and AP were recorded for up to 60 min after drug/solvent administration to assess short-term stability, and long-term stability was assessed by comparing 60 min control periods between the first and fifth experimental session up to a month apart.


RESULTS
Over 60 min in the control group, the UP remained steady, whereas the AP only decreased slightly. Recordings were made during five subsequent control periods, with at least 3 days of rest between successive assessments, and the UP and AP remained similar for up to 1 month. During a second phase, the effect of alpha 1-adrenoceptor agonists on both pressures were evaluated to characterize their functional uroselectivity. De-glymidodrine and L-phenylephrine (0.1 mg/kg) were administered intravenously; the UP increased by 18 cmH2O (146%) and 21 cmH2O (173%), respectively, whereas AP increased by 22 mmHg (31%) and 47 mmHg (63%), respectively. At 5 min after administering the drugs, the UP remained higher by 16 cmH2O (121%) with de-glymidodrine, whereas it had returned to basal values with L-phenylephrine.


CONCLUSIONS
This conscious-animal model allows the simultaneous measurement of UP and AP in the absence of anaesthesia. It provides a useful means to directly evaluate the effects of a drug on the urogenital and cardiovascular systems, and thereby its functional uroselectivity.
Pouyet
T B
TB
Department of Urology, Synthelabo Recherche, Rueil-Malmaison, France.
Briand
P G
PG
Martin
D J
DJ
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D011312:Pressure; D011817:Rabbits; D014521:Urethra / Q000502:physiology*; D014546:Urinary Catheterization; D014554:Urination / Q000502:physiology