Differential effects of chronic partial myelotomies on monoamine levels in cat spinal cord.

The concentrations of 5-hydroxytryptamine (5-HT), norepinephrine (NE) and dopamine (DA) were measured in samples of lumbar and cervical spinal cords from 6 cats with chronic (over 2 months) lesions of the thoracic spinal cord and from 7 unoperated cats. Lesions confined to the dorsal thoracic spinal cord significantly lowered lumbar concentrations of NE, but not 5-HT, compared with control lumbar or matched paired cervical samples. Both NE and 5-HT were significantly reduced by dorsal or ventral lesions that involved tissue ventral to the central canal. Only the largest lesion could be shown to reduce lumbar DA concentration.