title: Tetra-butyl ammonium attenuates evoked release of acetylcholine from mouse hemidiaphragm preparation.
abstract: Tetra-butyl ammonium is a homologous member of mono-quaternary ammonium salts, and it has been reported to have a property of nondepolarizing neuromuscular relaxant. However, no neurochemical evidences exist that tetra-butyl ammonium may interfere with quantal release of acetylcholine from motor nerve terminals. In this study, using the neurochemical method, we investigated the effect of tetra-butyl ammonium on stimulation-evoked release of acetylcholine from mouse hemidiaphragm preparation. The preparation was loaded with [3H]choline (5 microCi/ml). Low concentrations of tetra-butyl ammonium (10(-5) M) had no effects. On the other hand, at concentrations of 4x10(-5) and 10(-4) M, this compound significantly reduced the [Ca2+]o-dependent release of acetylcholine from phrenic nerves. This finding indicates that tetra-butyl ammonium possesses a presynaptic inhibitory effect on acetylcholine release from the phrenic nerve terminal.
authors.affiliation: Department of Anesthesiology, Oita Medical University, Hasama-machi, Oita, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Miyakawa
authors.forename: H
authors.initials: H
authors.lastname: Iwasaka
authors.forename: T
authors.initials: T
authors.lastname: Zelles
authors.forename: T
authors.initials: T
authors.lastname: Noguchi
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003902:Detergents / Q000494:pharmacology*; D003964:Diaphragm / Q000187:drug effects / Q000294:innervation / Q000378:metabolism; D008297:Male; D051379:Mice; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000378:metabolism; D010791:Phrenic Nerve / Q000187:drug effects* / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000187:drug effects* / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D013572:Synaptic Vesicles / Q000187:drug effects* / Q000378:metabolism
chemical_list: D003902:Detergents; D026902:Potassium Channel Blockers; D000644:Quaternary Ammonium Compounds; D015761:4-Aminopyridine; C009405:tetrabutylammonium; D000109:Acetylcholine