Organization of calcitonin gene-related peptide-immunoreactive terminals in the primate dorsal horn.
The present paper is concerned with the arrangement of axons and synaptic terminals immunostained for calcitonin gene-related peptide (CGRP), a primary afferent marker, in the primate (Macaca fascicularis) dorsal horn. The CGRP axons and terminals are uniformly distributed in laminae I and II outer (o) but they are concentrated laterally and distributed intermittently in the reticulated region of lamina V. A prominent bundle of labeled axons is seen in the sacral cord dorsal to the central canal. Emphasis is given to the relation of CGRP-immunoreactive terminals to other terminals, both labeled and unlabeled, in laminae I and IIo. In this regard, adjacent CGRP-immunoreactive terminals are often united by puncta adhaerentia. Of particular interest is the observation that CGRP-immunoreactive terminals can be found presynaptic to other terminals which sometimes resemble central primary afferent endings. In addition CGRP-immunoreactive terminals end on other CGRP terminals. Both findings suggest that primary afferent terminals interact synaptically with other primary afferent terminals.
Carlton
S M
SM
Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77550.
McNeill
D L
DL
Chung
K
K
Coggeshall
R E
RE
D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D007150:Immunohistochemistry; D008251:Macaca / Q000378:metabolism*; D008252:Macaca fascicularis / Q000033:anatomy & histology / Q000378:metabolism*; D008854:Microscopy, Electron; D009411:Nerve Endings / Q000032:analysis* / Q000648:ultrastructure; D009479:Neuropeptides / Q000032:analysis*; D013116:Spinal Cord / Q000032:analysis* / Q000648:ultrastructure
D009479:Neuropeptides; D015740:Calcitonin Gene-Related Peptide