title: Involvement of nitric oxide in the potentiation of neurogenic contraction by manganese and nickel ions in mouse urinary bladder.
abstract: Repetitive electrical field stimulation evoked muscle contractions of the isolated mouse detrusor strips, which could be abolished by tetrodotoxin (TTX). Both Mn2+ and Ni2+ (0.01-0.06 mM) enhanced neurogenic detrusor contractions in high Ca2+ (5 mM) medium. The non-cholinergic component of the evoked detrusor contractions (in the presence of atropine) was specifically sensitive to this enhancing effect by either Mn2+ or Ni2+. In contrast, the cholinergic component in alpha,beta-methylene ATP-treated detrusors remained unaffected. As compared with Mn2+ and Ni2+, other metal ions, Cu2+, Co2+, Cd2+ and UO2(2+), failed to enhancing the non-cholinergic component of neurogenic detrusor contractions. Nitric oxide synthase (NOS) inhibitors, NG-nitro-L-arginine methyl ester and 7-nitroindazole (a selective neuronal NOS inhibitor) markedly inhibited the enhancing effect by either Mn2+ or Ni2+ on the neurogenic detrusor contractions. Moreover, Mn2+ and Ni2+ did not affect the contractions induced by either carbachol or alpha,beta-methylene ATP. It is concluded from these findings that the neuronal NOS-NO generation pathway is apparently involved in the enhancing effect of Mn2+ and Ni2+ on the muscle contractions elicited by excitatory non-cholinergic neurotransmission in the mouse detrusor strips.
authors.affiliation: Institute of Toxicology, College of Medicine, National Taiwan University, Taipei.
authors.forename: S H
authors.initials: SH
authors.lastname: Liu
authors.forename: S Y
authors.initials: SY
authors.lastname: Lin-Shiau
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D046508:Culture Techniques / Q000379:methods; D004357:Drug Synergism; D008297:Male; D008345:Manganese / Q000494:pharmacology*; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D018377:Neurotransmitter Agents / Q000502:physiology; D009532:Nickel / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects
chemical_list: D002121:Calcium Channel Blockers; D018377:Neurotransmitter Agents; D009569:Nitric Oxide; D008345:Manganese; D009532:Nickel