Motor responses of the urinary bladder and skeletal muscle in Botulinum intoxicated rats

Abstract

Type A or type D [Clostridium] botulinum toxin administered to rats did not produce a generalized paralysis of skeletal muscles at the time of ventilatory arrest. However, if survival was extended by artificial ventilation complete blockade of neuromuscular iransmission developed 6.5 hr after 100 MLD [minimum lethal dose] of type D and 5 hr after 1000 MLD of type A toxin. The onset of paralysis of a muscle was shortened by repetitive stimulation of the motor nerves. There was no consistent blockade of parasympathetically innervated viscera in animals dying after type A toxin. Animals given type D toxin displayed mydriasis and urinary retention before death. Motor responses to electrical stimulation, of bladder preparations ;n vitro were more vulnerable to type D than to type A toxin. When somatic paralysis was complete in animals treated with type A or type D toxin the excised bladders produced pressure elevations 45 and 25%, respectively, of control preparations. During electrical stimulation of bladder preparations nearly paralysed by either toxin, the ACh [acetylcholine] release was significantly diminished from controls, in the rat bladder botulinum toxin specifically disrupted the liberation of mediator from post-ganglionic nerve endings.