RESUMEN
PURPOSE: We investigated the effects of the combination of bladder outlet obstruction and diabetes mellitus on in vitro rat bladder body strip function. MATERIALS AND METHODS: Longitudinal strips were removed from ventral and dorsal detrusor of age matched control, 2-week diabetic, 2-week obstructed and 2-week obstructed diabetic rats. Contractile responses to electrical field stimulation, carbachol, adenosine triphosphate, KCl and phenylephrine, and relaxations in response to norepinephrine and isoproterenol were measured. RESULTS: Bladders from diabetic, obstructed and obstructed diabetic rats were 1.6-fold, 2.6-fold and 3.6-fold heavier than those from controls. Responses of bladder strips from diabetics to all stimuli were similar to those of controls. Strips from obstructed rats were significantly less responsive to norepinephrine than those from controls or diabetics and strips from obstructed diabetics were significantly less responsive to norepinephrine and isoproterenol than those from all other groups. Strips from obstructed diabetics had significantly decreased responses to field stimulation, while responses to carbachol were decreased to a lesser extent. Responses of strips from obstructed rats to field stimulation were also decreased compared with controls but were significantly greater than those of the obstructed diabetic group. Responses to adenosine triphosphate, KCl and phenylephrine were similar in all groups. CONCLUSIONS: The combination of outlet obstruction and diabetes mellitus causes significant increases in bladder mass compared with either diabetes or obstruction alone. Bladder strips from obstructed diabetics show characteristics of denervation accompanied by alterations in beta-adrenergic function, suggesting that the coexistence of outlet obstruction and diabetes increases the rate of development of bladder decompensation.
Asunto(s)
Diabetes Mellitus Experimental/fisiopatología , Obstrucción del Cuello de la Vejiga Urinaria/fisiopatología , Vejiga Urinaria/fisiopatología , Animales , Diabetes Mellitus Experimental/complicaciones , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Técnicas In Vitro , Masculino , Norepinefrina/farmacología , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Vejiga Urinaria/efectos de los fármacos , Obstrucción del Cuello de la Vejiga Urinaria/complicacionesRESUMEN
PURPOSE: We investigated the relationship of bladder mass to responses to electrical field stimulation and adrenergic agonists in diabetic rat bladders. MATERIALS AND METHODS: Longitudinal strips were removed from the ventral and dorsal detrusor of age matched control, 2-month diabetic and sucrose drinking rats. Contractile responses to electrical field stimulation, KCl and phenylephrine, and relaxation in response to norepinephrine and isoproterenol were measured. RESULTS: Bladders from sucrose drinking and diabetic rats weighed significantly more than those of controls. Diabetic rats were divided into 2 groups with the bladder weighing less than or greater than 265 mg. Strips from small diabetic bladders were generally more responsive to field stimulation and norepinephrine than those from control or sucrose drinking rats. Conversely decreased function was especially apparent in dorsal strips from large diabetic bladders. Ventral strips were significantly more sensitive to the relaxant actions of norepinephrine and isoproterenol than dorsal strips. CONCLUSIONS: Our results suggest that the responsiveness of diabetic rat bladder to electrical field stimulation and adrenergic agonists is related to bladder mass, analogous to observations after partial outlet obstruction. Decreased function was particularly apparent in dorsal strips from diabetic rats with a large bladder.