Localization of hindlimb vasomotor neurones in the lumbar spinal cord of the guinea pig.

After retrograde labelling with horseradish peroxidase, sympathetic preganglionic neurones projecting to paravertebral ganglion cells with destinations primarily in the hindlimb were found to lie laterally in the intermediate region of the lumbar spinal cord. The majority of the labelled cell bodies were located near the edge of the grey matter or lateral to it within the white matter. In the most caudal segments (L3-L4) neurons extended right across the lateral funiculi. This distribution of neurones with predominantly vasoconstrictor functions differs markedly from that observed after labelling preganglionic fibres that project in the hypogastric nerve to the pelvic viscera.