Nm. Kheck et al., 5-HT1A RECEPTOR LOCALIZATION ON THE AXON HILLOCK OF CERVICAL SPINAL MOTONEURONS IN PRIMATES, Journal of comparative neurology, 355(2), 1995, pp. 211-220
Serotonin (5-HT) has direct and specific effects on the activity of sp
inal cord motoneurons. The 5-HT1A receptor has been shown to mediate m
otoneuron responses in spinal reflex pathways using the highly selecti
ve 5-HT1A receptor agonist 8-OH-DPAT. We have developed an antipeptide
antibody that recognizes a specific region (the second external loop)
of the 5-HT1A receptor. This 5-HT1A receptor antibody labels populati
ons of neurons and glia in the primate cervical spinal cord. The highe
st receptor density is present in the superficial lamina of the dorsal
horn, around the central canal, and on the axon hillock of large vent
ral horn motoneurons. The cellular labeling pattern on motoneurons sho
ws a single, densely stained, tapering process emanating from the peri
karyon. A more diffuse label is also present throughout the soma. Dend
ritic labeling was not apparent. These results suggest that post-synap
tic 5-HT1A receptors may be involved in modulating spinal motoneuron a
ctivity at the key site of action potential initiation, the axon hillo
ck. (C) 1995 Wiley-Liss, Inc.