Upper motor neurone effects in sheep of some beta-carboline alkaloids identified in zygophyllaceous plants.
The beta-carbolines harmane, norharmane, tetrahydronorharmane, harmine, harmaline and harmol were administered to sheep to assess their effects on upper motor neurone function. Harmane at a dose rate of 54 mg/kg induced hypomotility, head tremors, pelvic limb paresis, hypermetria and a wide based stance. A range of similar effects were observed with norharmane at the same dose rate. Tetrahydronorharmane at a dose rate of 54 mg/kg induced hypermotility followed by hypomotility, asymmetrical pelvic limb paresis, hypermetria, a wide based stance, and stereotyped eating behaviour. Harmine and harmaline at 6 mg/kg induced mild head and body tremors, and at 18 mg/kg induced hypomotility, intense head and body tremors, pelvic limb paresis, crossing over of limbs, neck extension and head swaying. Harmol was not effective at 54 mg/kg by either the subcutaneous or intraperitoneal routes, but at an intravenous dose of 27 mg/kg it induced hypermotility followed by hypomotility, body tremors, limb paresis, muscle asynergy, a wide based stance and jumping behaviour. Harmane, tetrahydronorharmane, harmaline and harmol were convulsive in some sheep at high dose rates.
Bourke
C A
CA
Agricultural Research and Veterinary Centre, Orange, New South Wales.
Carrigan
M J
MJ
Dixon
R J
RJ
D000470:Alkaloids / Q000633:toxicity*; D000818:Animals; D002243:Carbolines / Q000633:toxicity*; D005260:Female; D006246:Harmaline / Q000633:toxicity; D006247:Harmine / Q000031:analogs & derivatives / Q000633:toxicity; D008124:Locomotion / Q000187:drug effects*; D009046:Motor Neurons / Q000187:drug effects*; D010947:Plants, Toxic; D012756:Sheep / Q000502:physiology*
D000470:Alkaloids; D002243:Carbolines; C001326:harmol; D006247:Harmine; C009804:tryptoline; C005010:harman; C010262:norharman; D006246:Harmaline