Effects of MK-801 on rat primary afferent neurons and fibers.
Recent evidence suggests that glutamate and its N-methyl-D-aspartate (NMDA) receptor may participate in regulating neurite morphology and peptide expression. A previous study from this laboratory showed that treatment with the NMDA receptor antagonist, MK-801, induced an apparent increase in the density of calcitonin gene-related peptide (CGRP)-immunoreactive primary afferent fibers in the dorsal spinal cord of the rat. The present study was undertaken to extend this work by: 1) quantifying the MK-801-induced increase in CGRP immunostaining in the dorsal grey commissure/medial dorsal horn region and 2) examining the effect of MK-801 on the number of CGRP-immunoreactive primary afferent cell bodies in lumbar dorsal root ganglia. Following 7 days of MK-801 treatment, a significant increase (p less than 0.001) in CGRP immunostaining was observed in the dorsal grey commissure/medial dorsal horn. However, after MK-801 treatment, no significant difference was noted in the numbers of CGRP-immunoreactive primary afferent cell bodies in dorsal root ganglia. These data suggest that MK-801 produces significant alterations in the intraspinal projection of CGRP-immunoreactive fibers without inducing immunocytochemically detectable CGRP within a new population of primary afferent neurons.
McNeill
D L
DL
Department of Anatomical Sciences, University of Oklahoma, Oklahoma City 73190.
Sherburn
E W
EW
Galbraith
J M
JM
Klein
C M
CM
Westermeyer
M M
MM
Pilcher
B K
BK
Shew
R L
RL
Papka
R E
RE
D000344:Afferent Pathways / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis / Q000378:metabolism; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009132:Muscles / Q000294:innervation; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D010487:Periaqueductal Gray / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*
D016291:Dizocilpine Maleate; D015740:Calcitonin Gene-Related Peptide