Spinal shock: possible role of receptor plasticity and non synaptic transmission.

Spinal shock remains an enigma. To date there has been no convincing explanation of the recovery of reflexes following their complete abolition. Volume transmission includes both the activation of extrasynaptic receptors, and activity induced by substances diffusing into synaptic clefts via the extracellular fluid. A brief review of non synaptic transmission is given, and a review of spinal shock. We suggest that the recovery of reflexes in spinal shock may be related to the up regulation of receptors, resulting in increased sensitivity to neurotransmitters and other neuroactive substances released at the surviving synapses, or elsewhere, and transported in the extracellular fluid. Further understanding of spinal shock would give both practical help for the patient and have academic implications for the scientific basis of neurological rehabilitation.