The effects of acute and chronic botulinum toxin treatment on receptor number, receptor distribution and tissue sensitivity in rat diaphragm. 1977

L L Simpson

Tritiated alpha-bungarotoxin was used to determine the number and distribution of acetylcholine receptors in innervated, denervated and botulinum toxin-treated muscles. Innervated hemidiaphragms bound approximately 2.3 x 10(11) molecules of alpha-bungarotoxin; binding sites were restricted to the end-plate region. Neither acute denervation nor acute poisoning with botulinum toxin altered the number or distribution of alpha-bungarotoxin binding sites. In chronically denervated hemidiaphragms, there was an increase in alpha-bungarotoxin binding sites (maximum about 5.7 x 10(12); these sites were distributed across the muscle surface. In chronically poisoned hemidiaphragms, there was also an increase in the number (maximum about 4.7 x 10(12)) and distribution of binding sites. Chronic denervation and chronic botulinum toxin treatment both produced supersensitivity to acetylcholine. At maximal sensitivity, the respective ED50 values were: denervated muscle, 1.1 x 10(-6) M; botulinum toxin-treated muscle, 5.0 x 10(-6) M. The combination of denervation plus botulinum toxin treatment did not have additive or synergistic effects on alpha-bungarotoxin binding (4.9 x 10(12) molecules/hemidiaphragm) or on tissue sensitivity to acetylcholine (ED50 = 2.1 x 10(-6) M). It is concluded that denervation and botulinum toxin have rather similar effects on the number and distribution of acetylcholine receptors in rat hemidiaphragm.

UI MeSH Term Description Entries
D008297 Male Males
D009119 Muscle Contraction A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments. Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009121 Muscle Denervation The resection or removal of the innervation of a muscle or muscle tissue. Denervation, Muscle,Denervations, Muscle,Muscle Denervations
D009132 Muscles Contractile tissue that produces movement in animals. Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D009469 Neuromuscular Junction The synapse between a neuron and a muscle. Myoneural Junction,Nerve-Muscle Preparation,Junction, Myoneural,Junction, Neuromuscular,Junctions, Myoneural,Junctions, Neuromuscular,Myoneural Junctions,Nerve Muscle Preparation,Nerve-Muscle Preparations,Neuromuscular Junctions,Preparation, Nerve-Muscle,Preparations, Nerve-Muscle
D011950 Receptors, Cholinergic Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology. ACh Receptor,Acetylcholine Receptor,Acetylcholine Receptors,Cholinergic Receptor,Cholinergic Receptors,Cholinoceptive Sites,Cholinoceptor,Cholinoceptors,Receptors, Acetylcholine,ACh Receptors,Receptors, ACh,Receptor, ACh,Receptor, Acetylcholine,Receptor, Cholinergic,Sites, Cholinoceptive
D001905 Botulinum Toxins Toxic proteins produced from the species CLOSTRIDIUM BOTULINUM. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon ENDOCYTOSIS into PRESYNAPTIC NERVE ENDINGS. Once inside the cell the botulinum toxin light chain cleaves specific SNARE proteins which are essential for secretion of ACETYLCHOLINE by SYNAPTIC VESICLES. This inhibition of acetylcholine release results in muscular PARALYSIS. Botulin,Botulinum Neurotoxin,Botulinum Neurotoxins,Clostridium botulinum Toxins,Botulinum Toxin,Neurotoxin, Botulinum,Neurotoxins, Botulinum,Toxin, Botulinum,Toxins, Botulinum,Toxins, Clostridium botulinum
D002038 Bungarotoxins Neurotoxic proteins from the venom of the banded or Formosan krait (Bungarus multicinctus, an elapid snake). alpha-Bungarotoxin blocks nicotinic acetylcholine receptors and has been used to isolate and study them; beta- and gamma-bungarotoxins act presynaptically causing acetylcholine release and depletion. Both alpha and beta forms have been characterized, the alpha being similar to the large, long or Type II neurotoxins from other elapid venoms. alpha-Bungarotoxin,beta-Bungarotoxin,kappa-Bungarotoxin,alpha Bungarotoxin,beta Bungarotoxin,kappa Bungarotoxin
D003964 Diaphragm The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION. Respiratory Diaphragm,Diaphragm, Respiratory,Diaphragms,Diaphragms, Respiratory,Respiratory Diaphragms
D000109 Acetylcholine A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system. 2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine
Copied contents to your clipboard!