Korean J Urol.  2008 Sep;49(9):837-843.

The Different Mechanisms of Awake Micturitions between Male and Female Rats Using an Overactive Model with Intravesical PGE2 Instillation

• Lee BY
• Jin LH
• Yoon SM
• Lee T

Abstract

PURPOSE: We wanted to obtain informations on the different mechanisms of awake micturitions between male and female rats by using an overactive model with intravesical PGE2 instillation.
MATERIALS AND METHODS
Sprague Dawley rats(6 male, 6 female) were used. A catheter was implanted into the bladder to record the intravesical pressure. Three days later, the awake cystometry was performed, and PGE2 was given intravesically to induce detrusor overactivity(DO). With using the conventional pressure and volume parameters, a new parameter of flow pressure was investigated.
RESULTS
When recorded as the flow pressure, the male rats exhibited higher urethral resistance than did the female rats in the normal state. The male rats showed higher urethral resistances after DO was induced, than those before the DO. However, the female rats did not show increased urethral resistance after DO was induced.
CONCLUSIONS
An increase in urethral resistance through the outlet region was induced in male rats after intravesical PGE2 instillation, but this didn't occur in female rats. This result indicates that overactive bladder has different mechanisms and responses in different genders.

Keyword

Bladder; Male; Female; Urethra; Urodynamics

MeSH Terms

Animals
Catheters
Dinoprostone
Female
Humans
Male
Rats
Urethra
Urinary Bladder
Urinary Bladder, Overactive
Urodynamics
Dinoprostone

Figure

• 

  Fig. 1 Definition of flow pressure using the simultaneous intraurethral pressure. The point on the intravesical pressure indicated by the arrow is coincident with the abruptly increased urethral pressure, which means that this point is the flow pressure (A). The urethral pressure catheter was inserted into the urethral portion 3 mm proximal to the urethral orifice (B). There was a time difference (*) on the points between the flow pressure and the beginning of the volume increase on the curve. IVP: intravesical pressure, IUP: intraurethral pressure, Vol: voided volume.

• 

  Fig. 2 The pressure and volume parameters in the control and PGE2 instilled cycles of awake cystometry in the male and female rats. (A) Basal pressure. Both the male and female rats showed the increased basal pressures after PGE2 intravesical instillation as compared to the control cycles. (B) Flow pressure. The male rats showed increased flow pressures after PGE2 intravesical instillation as compared to the control cycles, but the female rats not show increased flow pressures. (C) Threshold pressure. (D) Micturition pressure. Both the male and female rats showed increased threshold and micturition pressures after PGE2 intravesical instillation as compared to the control cycles. (E) Micturition volume. (F) Micturition interval. Both the male and female rats showed a decreased micturition volume and micturition intervals after PGE2 intravesical instillation, as comparing to the control cycles. *p<0.05, **p<0.01, ***p<0.001.

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  Fig. 3 Representative tracings of the voiding phase in one cycle for the awake male and female cystometry with intravesical PGE2 instillation. (A) Control cycle of the male rat. (B) PGE2 instilled cycle of the male rat. (C) Control cycle of the female rat. (D) PGE2 instilled cycle of the female rat. The male rats showed increased flow pressure (↑) after PGE2 intravesical instillation as compared to the control cycle, but the female rats did not show this increase. IVP: intravesical pressure.

• 

  Fig. 4 Representative tracings of the total cycles for the awake male and female cystometry with intravesical PGE2 instillation. (A) Male. (B) Female. Both the male and female rats showed the features of overactive bladder after PGE2 intravesical instillation as compared to the control cycles, which are the increased pressure parameters and the decreased volume parameters. IVP: intravesical pressure.

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