Different distribution of nitric oxide synthase and soluble guanylyl cyclase activities in the detrusor and proximal urethra of the rabbit.
OBJECTIVE
We investigated the different distributions of nitric oxide synthase (NOS) and soluble guanylate cyclase activities in the detrusor and proximal urethra in the rabbit.


METHODS
The detrusor and proximal urethra were excised, the mucosa and muscularis were separated and each layer was homogenized to measure the activities of NOS as well as baseline and sodium nitroprusside (SNP) activated soluble guanylate cyclase. Isometric tension experiments were performed in detrusor and urethral strips with and without mucosa.


RESULTS
In the detrusor NOS and sodium nitroprusside activated soluble guanylate cyclase activities in the mucosa were much higher than in the muscularis. While in the proximal urethra NOS activity in the 2 layers was similar, SNP activated soluble guanylate cyclase activity in the muscularis was 2.8 times higher than in the mucosa. Removing the mucosa reduced nitric oxide (NO) mediated neurogenic relaxation in the proximal urethra, while no relaxation responses could be elicited by electrical field stimulation with or without mucosa in the detrusor. On the other hand, removing the mucosa did not affect SNP or 8-bromo-cyclic guanosine monophosphate induced relaxation in the detrusor and proximal urethra.


CONCLUSIONS
In the detrusor NOS and soluble guanylate cyclase activities were mainly detected in the mucosa, while in the urethra these activities were distributed throughout the mucosa and muscularis. Also, the mucosa in the urethra but not in the detrusor contributed to electrical field stimulation induced, NO mediated relaxation. These findings confirm previous studies demonstrating that NO has a different role in the detrusor than in the proximal urethra.
Masuda
Hitoshi
H
Department of Urology, Institute of Biomaterials and Bioengineering, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Okuno
Tetsuo
T
Suzuki
Masahito
M
Kihara
Kazunori
K
Goto
Moritaka
M
Azuma
Hiroshi
H
D000818:Animals; D006162:Guanylate Cyclase / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D011817:Rabbits; D014018:Tissue Distribution; D014521:Urethra / Q000201:enzymology*; D001743:Urinary Bladder / Q000201:enzymology*; D014563:Urodynamics / Q000502:physiology
D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase