Figure 2.

Blockade of AChRs increases motoneuron excitability to the same extent as axotomy. Each group of vertical bars show mean ± SEM of MG motoneuron rheobase from individual experiments. Top and bottom dashed lines represent, respectively, the mean of mean values for MG motoneuron rheobase current from control animals and from animals with axotomized MG motoneurons. Botox was injected once daily into the MG muscle for 2 consecutive days, and motoneurons were studied after a 3 d delay. α-Btx was injected once daily into the MG muscle for 4 consecutive days, and motoneurons were studied after an additional 2 d delay. Saline injections followed the same daily pattern used for α-btx. Statistical analysis showed that the effects of α-btx injections were indistinguishable from axotomy effects, whereas botox effects were indistinguishable from the effects of saline injections.