Comparative effects of in vitro ischemia on contractile responses of mouse and rat bladders to various forms of stimulation.
OBJECTIVE
To compare in an in vitro study the sensitivity of rat and mouse bladders to ischemia and reperfusion. Urinary bladder dysfunction is related to ischemia and reperfusion. Several studies have been conducted in which one animal model was used in the urinary bladder dysfunction experiments, but very few studies have compared the consequences of urinary bladder dysfunction in different species.


METHODS
Male rats and mice were anesthetized and their bladders removed. Bladder strips were placed in 15-mL baths containing oxygenated Tyrode's solution with glucose. Strips were stimulated by field stimulation, carbachol, and KCl, and the responses were recorded. Individual strips were switched for 1 hour to Tyrode's with no glucose equilibrated with nitrogen. During this hour, one half of the strips received repetitive stimulation. After the 1 hour of ischemia, the strips were returned to Tyrode's solution with glucose and oxygen for 1 hour without repetitive stimulation. The strips were restimulated as described above.


RESULTS
The rat bladder generated significantly greater tension than the mouse bladder. The responses of the mouse, but not the rat, bladder strips were suppressed after repetitive field stimulation in normal solution. In both species, the responses were suppressed under ischemic conditions with or without repetitive stimulation. The responses of the mouse bladders were more sensitive to ischemia and repetitive stimulation than rat bladders.


CONCLUSIONS
These results have demonstrated that the mouse bladder is more sensitive to ischemic stress than the rat bladder. This information would be important when choosing species for the study of ischemia and reperfusion.
Whitbeck
Catherine
C
Division of Basic and Pharmaceutical Sciences, Albany College of Pharmacy, Albany, New York 12208, USA.
Sourial
Michael W
MW
Sourial
Mariette
M
Levin
Robert M
RM
D000818:Animals; D004558:Electric Stimulation; D066298:In Vitro Techniques; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D051379:Mice; D009119:Muscle Contraction; D051381:Rats; D017207:Rats, Sprague-Dawley; D001743:Urinary Bladder / Q000098:blood supply* / Q000503:physiopathology*