Beneficial action of glucocorticoid treatment on neuromuscular transmission during early motor nerve degeneration.
The effects of a short-term, high-dose glucocorticoid pretreatment regimen (triamcinolone diacetate, 8 mg/kg i.m. daily for 7 days) were examined on neuromuscular transmission deficits observed in the in vivo cat soleus nerve-muscle preparation at 48 hr after soleus nerve transection. The pretreated preparations had 20% more functional motor nerve terminals than the untreated. This was evidenced by a significantly (P less than 0.01) lesser difference in the indirectly evoked isometric contractile tensions between the denervated muscle and the contralateral intact preparation as a result of prior glucocorticoid treatment. The glucocorticoid pretreatment also significantly improved the capacity of the trophically deprived soleus motor nerve terminals to maintain transmission during high-frequency activation (100 to 400 Hz for 10 s). Moreover, triamcinolone treatment before nerve transection completely prevented the development of an increased sensitivity to d-tubocurarine neuromuscular block in untreated, 48-h nerve-transected preparations. These results demonstrate an ability of an intensive high-dose glucocorticoid treatment to sustain single and repetitive neuromuscular transmission during early anterograde nerve degeneration.
D000818:Animals; D002415:Cats; D005260:Female; D008297:Male; D009046:Motor Neurons / Q000187:drug effects* / Q000502:physiology; D009119:Muscle Contraction; D009407:Nerve Block; D009410:Nerve Degeneration; D009469:Neuromuscular Junction / Q000187:drug effects*; D008249:Protein-Lysine 6-Oxidase / Q000037:antagonists & inhibitors; D012584:Sciatic Nerve / Q000601:surgery; D009435:Synaptic Transmission / Q000187:drug effects*; D014221:Triamcinolone / Q000031:analogs & derivatives* / Q000494:pharmacology; D014403:Tubocurarine
D014221:Triamcinolone; C030262:triamcinolone diacetate; D008249:Protein-Lysine 6-Oxidase; D014403:Tubocurarine