STUDIES ON THE NEUROMUSCULAR EFFECTS OF THE EXTRACTS OF ABRUS PRECATORIUS LINN
STUDIES ON THE NEUROMUSCULAR EFFECTS OF THE EXTRACTS OF ABRUS PRECATORIUS LINN
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Date
1982-09
Authors
AMOSUN, SEYI-'LADELE
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Abstract
Abrus precatorius Linn. was reported to be a
medicinal plant (Ghosal & Dutta, 1971). The seeds of
the plant have been reported to cause paralysis in
horses (Nwude, 1979). In order to determine if this
plant contributes to paralysis observed in humans at
the Physiotherapy Department, Ahmadu Bello University
Teaching Hospital, Zaria, Nigeria, an investigation
was carried out on the neuromuscular effects of the
crude water, petroleum ether and ethanol extracts of
the seeds, leaves and root of Abrus precatorius Linn.
Isolated toad's rectus abdominis, rat's phrenic
nerve-diaphragm muscle preparation, as well as chicks
were used in this study. Isometric contractions of the
muscle preparations were recorded by Ugo Basile
recording microdynamometer (model No. 7050) .
Only the ethanol extracts antagonised the effect
of acetylcholine on the isolated tissues.. The ethanol
extract of the seeds (0.1 - 1.6 mg/ml) inhibited
(32.00 - 84.33%) acetylcholine-induced contractions
of toad's rectus abdominis mucole. Similarly, the
ethanol extract of the leaves (1.0 - 8.0 mg/ml)
inhibited (21.77 - 80.02%) the acetylcholine-induced
contraction of the toad's rectus abdominis, while
the ethanol extract of the roots (0.5 - 4.0 mg/ml)
also inhibited (20.75 - 85.80%) the contraction of
the tissue. The antagonism was reversible. On the
rat's tissue, the ethanol extract of the seeds
(0.1 - 0.8 mg/ml) inhibited (0.1+2 - 77.50%) the
contraction of the diaphragm elicited by electrical
stimulation of the phrenic nerve. Similarly, the
ethanol extract of the leaves (0.5 - 4.0 mg/ml)
antagonised (0.99 - 89.83%) the contraction of the
diaphragm muscle via phrenic nerve stimulation, while
the ethanol extract of the roots (0.3 - 2.4 mg/ml)
inhibited (4.89 - 86.47%) the same contraction. The
antagonism in each case was potentiated by d-tubocurare
and reversed by eserine.
The inhibitory effect of the ethanol extracts
on the nerve-induced contraction of the rat's diaphragm
was potentiated in the presence of reduced Ca++
(1.25 mM), elevated Mg++ (2.50 mM) or reduced K+
(0.9 mM).
The hot water extracts of the seeds, leaves
and roots, and the petroleum ether extract of the
seeds induced spastic paralysis in five day old chick;;.
On the other hand, the ethanol extracts of the seeds.,
leaves and roots caused flaccid paralysis when injected
intravenously into chicks. The ethanol extract of
the seeds was most toxic, whereas that of the leaves
was least toxic on weight basis.
The ethanol extracts showed a similarity to
d-tubocurare vis-a-vis the pattern of neuromuscular
blockade. The present data indicate that the ethanol
extracts of the seeds, leaves and roots of Abrus
precatorius possess neuromuscular blocking effects.
Description
A thesis submitted to the Postgraduate School,
Ahmadu Bello University, in partial fulfillment
of the requirements for the degree M.Sc.
Pharmacology.
Department of Pharmacology
Faculty of Pharmaceutical Sciences
Ahmadu Bello University, Zaria.
September, 1982.
Keywords
STUDIES,, NEUROMUSCULAR,, EFFECTS,, EXTRACTS,, ABRUS,, PRECATORIUS,, LINN,