Experimental Myasthenia Gravis-like Neuromuscular Impairment with Cleisthanthus collinus Leaf Extract Administration in Rat
✍ Scribed by N. V. Nanda Kumar; K. M. Vijayalakshmi
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 581 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0951-418X
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✦ Synopsis
Intraperitoneal administration of a sublethal dose (120mg/kg body wt) of Cleistanthus couinus aqueous leaf extract (CCLE) was found to induce a neuromuscular disorder like myasthenia gravis in rats after 45 min. The neuromuscular junction (NMJ) blockade was analysed in uiuo in the sciatic nerve-anterior tibialiis muscle prpearation. The pattern of nerve evoked compound muscle action potentials (NCMAP) at various frequencies of supramaximal electrical stimulation from single to 100 Hz were recorded. Administration of CCLE showed a sequential decremental response in NCMAP resembling the established EMG patterns of myasthenia gravis (MG). The diagnostic tests, namely a transient improvement and repair of the decremental response in NCAMPs after administration of 4-aminopyridine (1 mglkg), a characteristic decrement in the 4th or 5th potential on lower frequencies of stimulation, an increased sensitivity to d-tubocurarine (120 pg/kg) and with least or marginal effect on CMAPs on direct muscle stimulation suggested an MG-like neuromuscular disorder which occurs due to ACh receptor blockade. Further, with prior administration of antisnake venon serum (AVS)an antiserum factor for krait alpha bungarotoxin, the NCMAP decremental response in both control and in CCLE administered rats was rectified transiently and also delayed the onset of NMJ blockade. It is suggested that the prolonged and irreversible effect of the leaf extract, unlike the reversible effect of curare, confers a sustained NMJ blockade required for inducing a MG-like condition.