Effects of spinal cord transection and MK-801 on CGRP immunostaining in the rat urinary bladder.
Numerous studies have demonstrated that lesions in the CNS can alter the density of sensory nerve processes in peripheral organs. In the present study, rat spinal cords were transected at the second lumbar segmental level and the density of calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers in the urinary bladder was examined. Additional rats had spinal cord transections followed by 12 days of treatment with the N-methyl-D-aspartate receptor antagonist, MK-801. In the bladders of control rats, CGRP-immunoreactive fibers were present as thick nerve trunks, perivascular plexi, and a fine meshwork of varicose nerve fibers. Twelve days following a spinal cord transection, the density of CGRP-immunoreactive nerve fibers was markedly reduced; occasional fibers appeared primarily as nonvaricose fine fibers. In bladders from rats receiving a spinal cord transection and MK-801 treatment, CGRP-immunoreactive fibers were abundantly distributed throughout the detrusor muscle; these fibers exhibited numerous varicosities as well as some enlarged terminal varicosities. These data demonstrate that (i) an upper motor neuron-type lesion markedly decreases the density of CGRP-immunoreactive peripheral afferent nerve processes and (ii) following a spinal cord transection, MK-801 appears to enhance the density of CGRP immunostaining in the bladder.
McNeill
D L
DL
Department of Anatomical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
Shew
R L
RL
Holzbeierlein
J M
JM
Papka
R E
RE
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D003714:Denervation; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D008297:Male; D009424:Nervous System Physiological Phenomena; D009434:Neural Pathways / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000502:physiology*; D001743:Urinary Bladder / Q000737:chemistry*
D016291:Dizocilpine Maleate; D015740:Calcitonin Gene-Related Peptide