Presynaptic and postsynaptic effects of local cathodal DC polarization within the spinal cord in anaesthetized animal preparations

摘要: Key points Trans-spinal DC stimulation affects both postsynaptic neurons and the presynaptic axons providing input to these neurons. In present study, we show that intraspinally applied cathodal current replicates effects of trans-spinal direct in deeply anaesthetized animals spinal during actual application a post-polarization period. Presynaptic local polarization were expressed an increase excitability skin afferents (in dorsal horn) group Ia motor nuclei), at least 30 min after application. However, although facilitation (i.e. more effective) activation motoneurons by stimuli nucleus was very potent application, it only negligible once discontinued. The results suggest prolonged are primarily associated with changes synaptic transmission. Abstract The study aimed compare actions cord, focusing on primary motoneurons. To reduce directly affected cord region, weak polarizing (0.1–0.3 μA) locally cats rats; within hindlimb nuclei caudal lumbar segments, or horn terminal projection area low threshold afferents. Changes activated intraspinal (20–50 μA) estimated using increases decreases compound action potentials recorded from roots peripheral nerves as their measure. assessed intracellularly monosynaptic EPSPs extracellular field (evoked nuclei, cutaneous horn). The intracellular records motoneuronal discharges ventral root muscle nerve. Cathodal found affect them different extent. markedly increased involve some actions, but negligibly themselves. Taken together, indicate long-lasting activity induced reflects transmission.