Effects of acepromazine maleate and phenoxybenzamine on urethral pressure profiles of anesthetized, healthy, sexually intact male cats.

OBJECTIVES

To evaluate the effects of 2 compounds with alpha adrenergic antagonist properties on the urethral pressures of anesthetized, healthy, sexually intact male cats, and to evaluate one of the compounds for effect on striated muscle.

ANIMALS: 20 healthy, sexually intact male cats.

PROCEDURE: Cats were anesthetized with halothane, and urethral pressure profilometry was performed before and after treatment. 125I-labeled alpha-bungarotoxin bound to nicotinic receptors of murine skeletal muscle was used in a competitive binding study with acepromazine maleate.

RESULTS

Acepromazine maleate significantly decreased intraurethral pressures in the preprostatic (19%) and prostatic (21%) regions of the urethra. There was no effect on the postprostatic/penile segment. Acepromazine did not inhibit 125I-labeled alpha-bungarotoxin binding to nicotinic receptors in murine skeletal muscle. Phenoxybenzamine significantly decreased intraurethral pressures (14%) in the preprostatic region of the urethra only.

CONCLUSIONS

Acepromazine maleate and phenoxybenzamine have effects on the smooth muscle of the urethra of healthy, male cats. Acepromazine has no effect on striated muscle.

CLINICAL RELEVANCE: alpha-Adrenergic compounds may be used in the pharmacologic management of feline urinary tract disease.