[The role of ATP-receptor in controlling the urinary bladder and urethral function in rats].
BACKGROUND
The detrusor contraction involves an atropine resistant, nonadrenergic noncholinergic (NANC), component. Since adenosine triphosphate (ATP) has been proposed as a NANC transmitter, the role of ATP-receptors in the lower urinary tract was examined.


METHODS
The isovolumetric bladder contractions and the urethral pressure were monitored after intra-arterial administration of ATP analogues and other drugs in 52 female SD rats under intraperitoneal urethane anesthesia.


RESULTS
alpha beta metATP induced a rapid, phasic increase of the maximal bladder pressure immediately after the drug administration, which was followed by a decrease during the P 2 X-purinoceptor desensitization period, but it did not affect the resting bladder pressure. RB-2 did not affect both the maximal bladder pressure and the resting bladder pressure. As for the urethral functions, alpha beta metATP induced a decrease of the resting urethral pressure during the P 2 X-purinoceptors desensitization period, while RB-2 induced a increase of the resting urethral pressure in contrast. ATP, alpha beta metATP and RB-2 did not changed the maximal urethral relaxation.


CONCLUSIONS
The results will indicate that ATP produces detrusor contractions through the P 2 X-purinoceptor. Although ATP dose not affect urethral relaxation during voiding phase, it controls the urethral tone during collecting phase by both the excitation of P 2 X-purinoceptor and the inhibition of P 2 Y-purinoceptor.
Otomo
R
R
Department of Urology, Akita University School of Medicine.
Shimoda
N
N
Satoh
S
S
Sato
K
K
Ogawa
O
O
Kato
T
T
D000818:Animals; D005260:Female; D008365:Manometry; D009119:Muscle Contraction; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D014521:Urethra / Q000502:physiology*; D001743:Urinary Bladder / Q000502:physiology*
D018048:Receptors, Purinergic P2