Exploring the mechanisms of intravesical electrical stimulation in the in vitro rat whole bladder after treatment with atropine, α,β-methylATP and tetrodotoxin.
OBJECTIVE
In a previous study, we showed that the working mechanism of intravesical electrical stimulation (IVES) is probably mainly nerve mediated. But even after bladder decentralization, IVES can induce detrusor contraction. This study explores the effect of IVES in decentralized bladders and the importance of receptors in the bladder wall for a response on IVES.


METHODS
IVES (10 Hz square wave pulses, 20 msec pulse duration, 6 mA) was used in the bladder of 16 female Sprague-Dawley rats. After repeating IVES after consecutive bilateral bladder nerves section (L6-roots, pelvic nerves, and major pelvic ganglion (MPG)), the bladders were mounted in a tissue bath. IVES was performed in the control (n=16), after administration of tetrodotoxin (TTX) (n=6), after atropine and atropine with α,β-methylATP (n=6), and after α,β-methylATP and α,β-methylATP with atropine (n=4). The IVES-induced pressure rise (ΔP) was recorded.


RESULTS
Maximum ΔP (maxΔP) after transection of the MPG was significantly lower than after pelvic nerves transection. Treatment with TTX and with α,β-methylATP plus atropine abolished ΔP. Atropine alone gave an insignificant decrease of maxΔP. Treatment with α,β-methylATP alone reduced maxΔP significantly.


CONCLUSIONS
IVES can evoke contractions in a decentralized bladder. IVES-induced contractions are not a result of direct muscle stimulation, but are nerve mediated, involving intramural innervation and several parts of the bladder innervation. IVES-evoked contraction can be divided in a, contraction duration determining, cholinergic part and a, contraction strength determining, purinergic part. The peripheral innervation could play a role in IVES treatment in patients with interrupted central reflex pathway.
De Bock
Filip
F
Department of Urology, Faculty of Medicine, University of Antwerp, University Hospital of Antwerp, Antwerp, Belgium.
De Wachter
Stefan
S
Wyndaele
Jean-Jacques
JJ
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000283:Administration, Intravesical; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000008:administration & dosage / Q000494:pharmacology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D005728:Ganglia, Sympathetic / Q000187:drug effects; D066298:In Vitro Techniques; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D010388:Pelvis / Q000294:innervation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012445:Sacrococcygeal Region / Q000294:innervation; D013126:Spinal Nerve Roots / Q000187:drug effects; D013779:Tetrodotoxin / Q000008:administration & dosage / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects* / Q000294:innervation / Q000502:physiology
D000779:Anesthetics, Local; D018727:Muscarinic Antagonists; D013779:Tetrodotoxin; D001285:Atropine; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate