title: Single-walled carbon nanotubes (SWCNTs) enhance KCl-, acetylcholine-, and serotonin-induced contractions and evoke oxidative stress on rabbit ileum.
abstract: We examined the effects of intravenous administration of purified arc-discharge single-walled carbon nanotubes (SWCNTs) on rabbit ileum to establish the possibility of using these SWCNTs as cell markers or drug carriers for the treatment of intestinal diseases. The SWCNT purification process eliminated carbonaceous impurities and decreased the amount of metals. SWCNTs increased the contractile responses induced by KCl, acetylcholine (ACh), and serotonin (5-HT) in rabbit ileum. Verapamil, apamin, glibenclamide, quinine and charybdotoxin reduced the contractile responses induced by ACh and 5-HT in ileum from rabbits treated with SWCNTs, indicating that voltage-dependent Ca2+ channels and small, intermediate, and large-conductance Ca(2+)-activated, ATP-sensitive, and voltage-dependent K+ channels are involved in these effects. Atropine and hexamethonium reduced the ACh response, indicating that muscarinic and nicotinic receptors are involved in this effect. Ondansetron and GR 113808 reduced the 5-HT response, indicating that serotonin 5-HT3 and 5-HT4 receptors are involved in this effect. SWCNTs increased the malondialdehyde plus 4-hydroxyalkenals and carbonyl levels in rabbit plasma and ileum, indicating that SWCNTs produce oxidative stress. SWCNTs did not produce relevant histological changes or modify the levels of the inflammatory mediators iNOS and COX-2 in the ileum. In conclusion, this study demonstrates that the intravenous administration of SWCNTs can evoke oxidative stress and affect contractility in rabbit ileum. These effects could reduce the possibility of using the arc-discharge SWCNTs as cell markers or drug carriers to treat intestinal diseases.
authors.forename: Laura
authors.initials: L
authors.lastname: Grasa
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ansón-Casaos
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Martínez
authors.forename: Raquel
authors.initials: R
authors.lastname: Albendea
authors.forename: Alba
authors.initials: A
authors.lastname: De Martino
authors.forename: Sergio
authors.initials: S
authors.lastname: Gonzalo
authors.forename: María Divina
authors.initials: MD
authors.lastname: Murillo
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D005769:Gastrointestinal Motility / Q000187:drug effects; D007082:Ileum / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000648:ultrastructure; D018384:Oxidative Stress / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology*; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology*
chemical_list: D037742:Nanotubes, Carbon; D012701:Serotonin; D011189:Potassium Chloride; D000109:Acetylcholine