Morphology and Synaptic Pattern of Calretinin-immunoreactive Neurons in the Superficial Dorsal Horn of the Rat Spinal Cord / 대한해부학회지

ABSTRACT

The distribution and the synaptic relationships of calretinin-immunoreactive neurons were studied in the superficial dorsal horn of the rat spinal cord. Calretinin-immunoreactive neurons and fibers were found in all laminae of spinal cord. The densest staining of both cell bodies and fibers occurred in the superficial laminae. In lamina I, marginal cells and other neurons with small round cell bodies showed calretinin-like immunoreactivity. A calretinin-immunoreactive plexus of nerve fibers was also found in this lamina. Lamina II was densely packed with calretinin-immunoreactive neuronal elements. The outer layer of lamina II was primarily composed of calretinin-immunoreactive neurons with a round or oval shape, whereas in the inner layer dorsoventrally orientated labeled neurons with spindle-shaped cell bodies were observed. Densely labeled neuropils with punctate profiles were also seen. By electron microscopy most of the labeled punctate profiles appeared to be dendrites, but axonal profiles were also found in smaller numbers. Labeled dendritic profiles established symmetric or asymmetric synapses with unlabeled axons and labeled axons established primarily symmetric synaptic contacts with unlabeled dendrites. Synaptic contacts between two calretinin-immunoreactive processes were observed infrequently.