title: Inhibitory Effects of Botulinum Toxin Type A on Pyloric Cholinergic Muscle Contractility of Rat.
abstract: Botulinum toxin type A (BTX-A) selectively cleaves synaptosomal-associated protein of 25 kDa (SNAP-25) and results in inhibition of the fusion of synaptic vesicles containing neurotransmitters with the presynaptic membrane to undergo exocytosis and release. The aim of this study was to investigate whether BTX-A inhibited the pyloric smooth muscle contractility induced by acetylcholine (ACh) after BTX-A-mediated cleavage of SNAP-25 antagonized by toosendanin (TSN). Three groups of rat pyloric muscle strips were studied in vitro. All strips were allowed to equilibrate for 52 min under a basal loading tension of 1 g in Krebs solution and spontaneous contractile waves were recorded as their own controls before adding each drug. According to experimental protocols, 100 μM ACh, 1 μM atropine, 29.6 μM TSN and 10 U/ml BTX-A was added, respectively. BTX-A directly inhibited pyloric spontaneous contraction and ACh-induced contractile response. Addition of 10 U/ml BTX-A still inhibited pyloric smooth muscle contractility following incubation of TSN, while subsequent administration of 100 μM ACh had no effect. BTX-A inhibits pyloric smooth muscle contractility in our study suggesting BTX-A inhibits not only ACh release from cholinergic nerves but also muscarinic cholinergic muscular transmission.
authors.affiliation: Medical School, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Hospital of Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China.
authors.forename: Hong-Xu
authors.initials: HX
authors.lastname: Sun
authors.affiliation: Medical School, Jiangnan University, Wuxi 214122, Jiangsu, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Chu
authors.affiliation: Department of Neuroscience, Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, Gansu, People's Republic of China.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Hou
mesh_terms: D000109:Acetylcholine; D000818:Animals; D019274:Botulinum Toxins, Type A / Q000494:pharmacology* / Q000627:therapeutic use; D059329:Cholinergic Neurons / Q000187:drug effects; D004365:Drugs, Chinese Herbal; D018589:Gastroparesis / Q000188:drug therapy; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D011708:Pylorus / Q000187:drug effects*; D017207:Rats, Sprague-Dawley; D050825:Synaptosomal-Associated Protein 25 / Q000378:metabolism; D014315:Triterpenes
chemical_list: D000109:Acetylcholine; D019274:Botulinum Toxins, Type A; D004365:Drugs, Chinese Herbal; D050825:Synaptosomal-Associated Protein 25; C494210:Snap25 protein, rat; C036454:toosendanin; D014315:Triterpenes