Glucocorticoid preservation of motor nerve function during early degeneration

In cats, an intensive short‐term triamcinolone regimen prior to section of the soleus motor nerve significantly reduced the excitability loss that otherwise would have occurred over a 48‐hour period in its axons and terminals. The triamcinolone effect was manifested chiefly by striking preservation and enhancement of the capacity of soleus motoneurons to generate posttetanic repetition (PTR). This triamcinolone effect was also reflected by the greatly augmented posttetanic potentiation (PTP) obligatory to the neurogenic PTR. These principal effects were supported by an improvement in the capacity of the 48‐hour denervated system to maintain repetitive transmission and to recover from high‐frequency nerve stimulation. Overall, these results indicate that glucocorticoids can preserve excitability in degenerating motoneurons by a direct action. These findings provide a new basis for understanding clinical improvements that may be seen with intensive glucocorticoid therapy in certain neurological disorders.