title: Propulsive activity induced by sequential electrical stimulation in the descending colon of the pig.
abstract: This work was performed to study electrically induced contractions in the descending colon of pigs. Contractions were monitored using impedance planimetry and manometry. The luminal pressure, cross-sectional area (CSA), latency and velocity of CSA decrease were compared when using 3 ms, 9, 12, 15 or 30 mA pulses at 10 Hz for 10 s, and 15 mA, 0.03, 0.3 or 3 ms pulses at 10 Hz for 10 s. Stimulation was performed prior and after the application of N(G)-nitro-L-arginine methyl ester (L-NAME) and atropine. In the untreated colon, contraction was always of an 'off' type. A current increase from 9 to 30 mA increased the pressure. An increase of pulse duration from 0.03 to 3 ms shortened the latency, accelerated contraction and increased pressure. By sequential stimulation, contractions were coordinated to propel semi-fluid and solid luminal contents. L-NAME increased the magnitude of CSA decrease. Atropine induced inhibitory effects on contractions elicited by 3 ms pulses and abolished contractions induced by 0.03 and 0.3 ms pulses.
  
  
  CONCLUSIONS
  (i) electrical stimulation evokes'off' colon contractions, which can be coordinated to result in propulsion; (ii) the best combination for current and pulse duration to induce propulsive contractions is 15 mA and 3 ms; (iii) nitrergic and cholinergic pathways mediate responses to electrical stimulation.
authors.affiliation: Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Denmark. sevcr@smi.auc.dk
authors.forename: C
authors.initials: C
authors.lastname: Sevcencu
authors.forename: N J M
authors.initials: NJ
authors.lastname: Rijkhoff
authors.forename: H
authors.initials: H
authors.lastname: Gregersen
authors.forename: T
authors.initials: T
authors.lastname: Sinkjaer
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D003106:Colon / Q000294:innervation / Q000502:physiology*; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology; D010275:Parasympathetic Nervous System / Q000502:physiology; D010276:Parasympatholytics / Q000494:pharmacology; D013552:Swine
chemical_list: D004791:Enzyme Inhibitors; D010276:Parasympatholytics; D009569:Nitric Oxide; D001285:Atropine; D019331:NG-Nitroarginine Methyl Ester