Analysis of calcitonin gene-related peptide-like immunoreactivity in the cat dorsal spinal cord and dorsal root ganglia provide evidence for a multisegmental projection of nociceptive C-fiber primary afferents

1990 ◽  
Vol 302 (3) ◽  
pp. 562-574 ◽  
Author(s):  
Richard J. Traub ◽  
Barbara Allen ◽  
Emma Humphrey ◽  
M. A. Ruda
Keyword(s):  
Spinal Cord ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Calcitonin Gene Related Peptide ◽  
Primary Afferents ◽  
Dorsal Spinal Cord ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
C Fiber ◽  
Dorsal Spinal

Plasticity of calcitonin gene related peptide neurotransmission in the spinal cord during peripheral inflammation

1995 ◽  
Vol 73 (7) ◽  
pp. 1007-1014 ◽  
Author(s):  
V. S. Seybold ◽  
M. T. Galeazza ◽  
M. G. Garry ◽  
K. M. Hargreaves
Keyword(s):  
Spinal Cord ◽  
Calcitonin Gene Related Peptide ◽  
Peripheral Inflammation ◽  
Afferent Neurons ◽  
Dorsal Spinal Cord ◽  
Primary Afferent Neurons ◽  
Primary Afferent ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
Dorsal Spinal

Injection of complete Freund's adjuvant (CFA; 75 μL) into the plantar surface of the hind paw of the rat results in a mild inflammation that lasts for several days and is accompanied by hyperalgesia. Multiple components of calcitonin gene related peptide (CGRP) neurotransmission in the spinal cord are altered during the course of this peripheral inflammation. The content of immunoreactive (i) CGRP in the dorsal horn of the spinal cord, where primary afferent neurons terminate, is significantly decreased within 2 days after injection of CFA but increases to a level greater than that of the control at 8 days. The early decrease in iCGRP in the spinal cord suggests that the release of CGRP from primary afferent neurons is increased during the period of maximal hyperalgesia that accompanies peripheral inflammation. Changes in the mRNA for CGRP suggest that the increase in spinal content of iCGRP is due to an increase in synthesis of the peptide as the level of mRNA for CGRP is increased from 2 to 8 days after injection of CFA. Despite the decrease in the content of iCGRP in the spinal cord, there is no apparent decrease in the amount of iCGRP that can be released from the dorsal spinal cord by capsaicin; in fact, capsaicin-evoked release is increased at 4 days. Measurements of the binding of 125I-labelled CGRP in the dorsal spinal cord indicate that high affinity binding sites for CGRP are downregulated at 4 days after injection of CFA. In total, these data support the hypothesis that the activity of CGRP-containing primary afferent neurons is increased during peripheral inflammation. CGRP released from primary afferent neurons in the spinal cord may contribute to cellular changes that accompany peripheral inflammation.Key words: calcitonin gene related peptide, dorsal root ganglion, hyperalgesia, inflammation, spinal cord.

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