| Evidence Sentence: |
The aim of this study was to investigate whether expression of gamma-aminobutyric acid (GABA) and the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) in the primary sensory neurons of cervical dorsal root ganglia (DRG) are involved in electroacupuncture (EA)-induced analgesia in a rat model of incisional neck pain. |
| Evidence Sentence: |
30 min later, the rats were euthanased and cervical (C3-6) DRGs removed for measurement of immunoreactivity and mRNA expression of SP/CGRP and the GABAergic neuronal marker glutamic acid decarboxylase 67 (GAD67). |
| Evidence Sentence: |
Additionally, EA at LI18 and LI4-PC6 markedly suppressed neck incision-induced upregulation of mRNA/protein expression of SP/CGRP, and upregulated mRNA/protein expression of GAD67 in the DRGs of C3-6 segments. |
| Evidence Sentence: |
EA at LI18/LI4-PC6 increases PT in rats with incisional neck pain, which is likely related to downregulation of pronociceptive mediators SP/CGRP and upregulation of the inhibitory transmitter GABA in the primary sensory neurons of cervical DRGs. |
| Evidence Sentence: |
Effects of EA on SP and CGRP immunoreactivity |
| Evidence Sentence: |
Immunofluorescence staining showed that SP- and CGRP-IR positive substances were granular in appearance and distributed throughout the cytoplasm. |
| Evidence Sentence: |
The SP- and CGRP-IR positive nerve fibres were also found between neuronal cell bodies. |
| Evidence Sentence: |
The diameters of SP- and CGRP-IR positive neurons ranged from 8-40 microm, being in the range of small- (diameter <30 microm) and medium- (31-40 microm in diameter) sized cells (figures 2A and 3A). |
| Evidence Sentence: |
As shown in figures 2B and 3B, the proportions of SP- and CGRP-IR positive neurons were notably greater in the model group relative to the normal group at 48 hours post-surgery (p=0.01 and p<0.001, respectively). |
| Evidence Sentence: |
By contrast, the proportion of CGRP-IR positive neurons tended to be higher in the ST36-GB34 group versus the model group (p=0.07), while the proportion of SP-IR positive neurons did not differ significantly (p=0.396). |
| Evidence Sentence: |
Effects of EA on mRNA expression of SP, CGRP and GAD67 |
| Evidence Sentence: |
The results of the qRT-PCR showed that, compared with the normal group, mRNA expression of SP and CGRP in the C3-6 DRGs was significantly increased in the model group versus the normal group (p<0.001 each; figure 5A,B). |
| Evidence Sentence: |
After the EA intervention, the increased mRNA expression of SP and CGRP was greatly downregulated in LI18 and LI4-PC6 groups (all p<0.001), but only slightly lower in the ST36-GB34 group, once again demonstrating a statistical tendency towards a significant difference relative to the model group (p=0.058 and p=0.054, respectively). |
