| Evidence Sentence: |
The roles of increased SP in Neuro-Sps were also investigated by using immunohistochemistry, in vivo single-fiber peripheral nerve recordings, and in vivo midbrain extracellular recordings. |
| Evidence Sentence: |
The Neuro-Sps showed an increased release of SP from afferent nerve terminals. |
| Evidence Sentence: |
Single fiber recordings of peripheral nerves showed that increased SP into the Neuro-Sps elevated the sensitivity of A- and C-fibers in response to acupuncture stimulation. |
| Evidence Sentence: |
In addition, the discharge rates of spinal wide dynamic response (WDR) neurons significantly increased following SP or acupuncture treatment in Neuro-Sps in normal rats, but decreased following the injection of CP-99994 into Neuro-Sps in IMH rats. |
| Evidence Sentence: |
Our findings suggest that SP released during neurogenic inflammation enhances the responses of sensory afferents to the needling of acupoints and triggers acupuncture signaling to generate acupuncture effects. |
| Evidence Sentence: |
To examine the increased release of SP from afferent nerves in Neuro-Sps, immunohistochemical detection of SP was performed on tissue samples from wrist areas of naive (Control) and IMH rats (Fig. |
| Evidence Sentence: |
IMH rats (Hypertension, n = 6) showed enhanced SP expression in Neuro-Sps compared to control rats (n = 6; one-way repeated ANOVA, F(2,10) = 37.404, p < 0.001; Fig. |
| Evidence Sentence: |
Furthermore, the increase of SP in acupoints of IMH rats was not observed in non-acupoint areas (data not shown). |
| Evidence Sentence: |
To further determine whether acupuncture itself can increase SP release, MAI acupuncture stimulation was applied to the wrist area for 20 sec at 1 min-intervals for a total of 10 min in naive rats (n = 6), revealing the enhanced expression of SP in the acupuncture-stimulated skin (Fig. |
| Evidence Sentence: |
To explore whether SP is involved in the effects of acupuncture on hypertension, we injected either vehicle (saline) or the SP receptor antagonist CP-99994 into Neuro-Sps over the wrist (mostly, PC6) 20 min prior to acupuncture in IMH rats. |
| Evidence Sentence: |
To determine whether an artificial increase in the SP level at acupoints generates acupuncture-like effects, subcutaneous injections of SP into Neuro-Sps were carried out in IMH rats. |
| Evidence Sentence: |
While IMH rats given vehicle developed hypertension, SP injection into Neuro-Sps near the wrist significantly inhibited the development of hypertension and mimicked acupuncture's effect (SP: two-way repeated ANOVA; group (1,4) = 7.746, p = 0.05; time F(12,48) = 21.941, p < 0.001; interaction (12,48) = 2.976, p = 0.004; Fig. |
| Evidence Sentence: |
It is known that capsaicin (CAP) induces the release of SP from primary afferent fibers. |
| Evidence Sentence: |
To further confirm that the elevation of SP levels in Neuro-Sps leads to the effects of acupuncture, we evaluated the effects of CP-99994 injections into Neuro-Sps. |
| Evidence Sentence: |
The subcutaneous injection of CAP mimicked the inhibitory effect of acupuncture or SP on the development of hypertension in IMH rats, which was prevented by pretreatment with CP-99994 (CAP: two-way repeated ANOVA; group F(1,4) = 34.336, p = 0.004; time F(12,48) = 84.843, p < 0.001; interaction F(12,48) = 4.768, p < 0.001; Fig. |
| Evidence Sentence: |
In another set of experiments, we determined the levels of plasma extravasation 2 h after the injection of vehicle (n = 9) or SP (n = 9) in naive and IMH rats and found significantly higher levels of plasma extravasation in wrist acupoints of SP-injected rats than in those of vehicle-injected rats, as shown in 3D skin images (Fig. |
| Evidence Sentence: |
Overall, these results suggest that the local release of SP in Neuro-Sps is closely linked to the effects of acupuncture. |
| Evidence Sentence: |
To determine whether SP increases the sensitivity of primary afferent fibers to acupuncture, single fiber recordings of peripheral nerves were performed in 15 somatic afferent neurons innervating the wrist area in 15 naive rats (Fig. |
| Evidence Sentence: |
4A), the rats given intradermal SP into the receptive field over the wrist showed a 2-fold increase in A-fiber afferent discharges (70.89 +- 1.15 impulses/sec) compared to the rats in the vehicle group (33.33 +- 0.71 impulses/sec; t-test, p < 0.001; Fig. |
| Evidence Sentence: |
The activity of C-fibers during acupuncture stimulation was also examined following intradermal SP injection. |
| Evidence Sentence: |
Next, we explored whether the activity of spinal dorsal horn neurons was enhanced by intradermal SP injection in normal rats and reversed by the subcutaneous injection of an SP receptor antagonist, CP-99994, into neurogenic acupoints in IMH rats. |
| Evidence Sentence: |
The responses of dorsal horn WDR neurons to mechanical stimuli were compared after injection with either saline (n = 11) or SP (n = 9) in normal rats. |
| Evidence Sentence: |
On the other hand, intradermal SP injection resulted in significantly increased evoked activity in response to a 60 g bending force (5 min, 19.16 +- 2.03; 10 min, 20.96 +- 2.62; 30 min, 22.29 +- 2.09 spikes/sec, respectively) compared to that observed in the saline group (one-way repeated ANOVA, 5 min: F(1,8) = 7.942, p = 0.023; 10 min: F(1,8) = 24.551, p = 0.001; 30 min: F(1,8) = 20.332, p = 0.002; Fig. |
| Evidence Sentence: |
However, there were no differences in the WDR discharge rates in response to bending forces of 2, 8.5 and 15 g between the saline and SP groups (Supplementary Fig. |
| Evidence Sentence: |
This suggests that SP increased the mechanical sensitivity to noxious stimulation, but not non-noxious stimulation. |
| Evidence Sentence: |
This result suggests that blockade of SP by CP-99994 at Neuro-Sps inhibited the WDR activities in IMH rats. |
| Evidence Sentence: |
This indicates that acupuncture effects on the activity of WDR neurons are associated with SP. |
| Evidence Sentence: |
Overall, these data indicate that increased SP release in acupoints enhanced mechanical sensitivity to noxious stimuli such as needles. |
| Evidence Sentence: |
To further confirm that the elevation of subcutaneous SP levels in Neuro-Sps is associated with the rVLM activation following acupuncture, we injected CAP into Neuro-Sps to induce SP release and measured the excitability of rVLM neurons. |
| Evidence Sentence: |
6D, E), suggesting that the increased levels of SP in acupoints contributed to enhanced firing activities of rVLM and generated acupuncture effects in IMH rats. |
| Evidence Sentence: |
The role of substance P in acupuncture signal transduction and effects |
| Evidence Sentence: |
Increased substance P in neurogenic spots |
| Evidence Sentence: |
Mediation by substance P of the inhibitory effects of acupuncture on the development of hypertension |
| Evidence Sentence: |
Enhancement by substance P of acupuncture-induced afferent fiber activation |
| Evidence Sentence: |
Substance P-induced enhancement of spinal WDR neuron activity |
