Effect of stimulation intensity and botulinum toxin isoform on rat bladder strip contractions

Christopher P. Smith, Timothy B. Boone, William C. De Groat, Michael B. Chancellor, George T. Somogyi

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

The present experiments compared the inhibitory effects of botulinum toxin A (BoNT-A) and botulinum toxin D (BoNT-D) on neurally evoked contractions of rat bladder strips. We examined the effect of fatigue (trains of 100 shocks at 20 Hz every 20 s for 10 min) followed by non-fatigue stimulation (trains of 100 shocks at 20 Hz every 100 s for 20 min) on the onset of effect and potency of the two toxins. For non-fatigue experiments, strips were untreated (n = 4); or incubated with 1.36 nM BoNT-A (n = 4). During fatigue experiments, strips were untreated (n = 5); or treated with either 1.36 nM BoNT-A (n = 6) or 0.8 nM BoNT-D (n = 6). In non-fatigue experiments, BoNT-A produced significant decreases in contractile area after 1 h of stimulation compared to untreated strips (P < 0.05). After three series of fatigue stimulation, differences in recovery amplitude and area between untreated versus BoNT-A, and untreated versus BoNT-D bladder strips, were statistically significant (P < 0.05). The onset of inhibitory effect was quicker in BoNT-D-treated strips, as a significant reduction (P < 0.05) in recovery of contractile area was observed after 1 h of stimulation compared to both untreated and BoNT-A-treated preparations. In addition, treated (BoNT-A and BoNT-D) and untreated bladder strips responded similarly to atropine, suggesting that the effects of BoNT result from inhibition of both acetylcholine and ATP release. Our results demonstrate that BoNT-D may be a more effective agent to inhibit transmitter release from autonomic nerves of the rat lower urinary tract. Moreover, in our hands, non-fatigue stimulation is as effective as fatigue stimulation in inhibiting bladder strip contractions.

Original languageEnglish (US)
Pages (from-to)165-171
Number of pages7
JournalBrain Research Bulletin
Volume61
Issue number2
DOIs
StatePublished - Jul 15 2003

Keywords

  • Bladder
  • Botulinum toxin
  • Contraction
  • Electrical stimulation

ASJC Scopus subject areas

  • Neuroscience(all)

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