COMPARATIVE BIOCHEMICAL CHARACTERISTICS OF THE CAT AND RABBIT URINARY-BLADDER

The cat and the rabbit are two of the most popular models for the stud y of lower urinary bladder function. The cat has been used extensively for in vivo studies of spinal and supra-spinal micturition reflexes. In contrast, the rabbit has been used extensively for the in vitro stu dy of bladder function. Although the cat and rabbit bladders are appro ximately the same mass, the cat bladder can generate approximately 6 t imes the intravesical pressure than the rabbit bladder at the same vol ume (in vitro response to field stimulation). In order to determine if the increased pressure generation is related to increased cellular en ergetics, we compared the intracellular concentrations of ATP and crea tine phosphate (CP), and the enzyme activities of three enzymes which have important functions in cellular energetics: creatine kinase, citr ate synthase, and malic dehydrogenase between the cat and rabbit urina ry bladder. The results can be summarized as follows: (1) The bladder weight of the cat and rabbit are similar. (2) The isolated cat bladder can generate approximately 6 times the intravesical pressure of the i solated rabbit bladder. (3) The ATP and CP concentrations of the rabbi t are significantly greater than the concentrations in the cat bladder . (4) The hydroxyproline concentration is significantly greater in the cat than the rabbit. (5) The maximum activities of creatine kinase, c itrate synthase, and malic dehydrogenase are significantly lower in th e cat than the rabbit. In general, it is clear that the ability of the cat to generate high intravesical pressures is not correlated with in creased tissue high energy phosphate concentrations, or high enzymatic activities of three specific cytosolic or mitochondrial enzymes. (C) 1994 Wiley-Liss. Inc.