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Analgesic effect of intrathecal gabapentin in a rat model of persistent muscle pain.

Kang TW, Sohn MK, Park NK, Ko SH, Cho KJ, Beom J, Kang S - Ann Rehabil Med (2014)

Bottom Line: There was a significant improvement on the mechanical threshold after administration of 100, 300, and 1,000 µg gabapentin compared to pre-injection and the control group.The analgesic effect continued for 105, 135, and 210 minutes, respectively.To discern side effects, motor function was measured.

View Article: PubMed Central - PubMed

Affiliation: Department of Physical Medicine and Rehabilitation, Sun General Hospital, Daejeon, Korea.

ABSTRACT

Objective: To evaluate the analgesic effect of intrathecal gabapentin therapy on secondary hyperalgesia in a rat model of persistent muscle pain.

Methods: Intrathecal catheters were implanted into rats. Mechanical secondary hyperalgesia was induced by repeated intramuscular injections of acidic solution into the gastrocnemius muscle. Gabapentin was administrated intrathecally. Rats were allocated to control and experimental (gabapentin 30, 100, 300, and 1,000 µg) group. After gabapentin administration, mechanical withdrawal threshold was measured every 15 minutes and the motor function was measured 30 minutes later.

Results: Mechanical hyperalgesia was evoked after the second acidic buffer injection. There was a significant improvement on the mechanical threshold after administration of 100, 300, and 1,000 µg gabapentin compared to pre-injection and the control group. The analgesic effect continued for 105, 135, and 210 minutes, respectively. To discern side effects, motor function was measured. Motor function was preserved in both groups after gabapentin administration, except for rats who received 1,000 µg gabapentin.

Conclusion: Intrathecal gabapentin administration produces dose-dependent improvements in mechanical hyperalgesia in a persistent muscle pain rat model. This implicates the central nervous system as having a strong influence on the development of persistent mechanical hyperalgesia. These results are helpful in understanding the pathophysiology of secondary hyperalgesia and in the treatment of patients with chronic muscle pain.

No MeSH data available.


Related in: MedlinePlus

Treadmill motor function test determined by measurements on exercise time at 5° inclination and 17 m/min speed.
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Figure 2: Treadmill motor function test determined by measurements on exercise time at 5° inclination and 17 m/min speed.

Mentions: Each group was tested for the motor function with the treadmill (Daejong E&C, Daejeon, Korea) before and 30 minutes after receiving gabapentin. The treadmill was equipped with electrified steel bars on the lower part to make rats continue running forward (Fig. 2). As a preliminary exercise for adaptation to the treadmill, all rats were subjected to a daily 5-minute exercise at 5° inclination and a treadmill speed of 15 m/min for 2 days prior to the first gabapentin injection. In the motor function tests, the treadmill was slowly sped up to 17 m/min at a 5° inclination, which was then maintained. The run times were measured, and the test was ended if a rat ran more than 150 seconds.


Analgesic effect of intrathecal gabapentin in a rat model of persistent muscle pain.

Kang TW, Sohn MK, Park NK, Ko SH, Cho KJ, Beom J, Kang S - Ann Rehabil Med (2014)

Treadmill motor function test determined by measurements on exercise time at 5° inclination and 17 m/min speed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4221397&req=5

Figure 2: Treadmill motor function test determined by measurements on exercise time at 5° inclination and 17 m/min speed.
Mentions: Each group was tested for the motor function with the treadmill (Daejong E&C, Daejeon, Korea) before and 30 minutes after receiving gabapentin. The treadmill was equipped with electrified steel bars on the lower part to make rats continue running forward (Fig. 2). As a preliminary exercise for adaptation to the treadmill, all rats were subjected to a daily 5-minute exercise at 5° inclination and a treadmill speed of 15 m/min for 2 days prior to the first gabapentin injection. In the motor function tests, the treadmill was slowly sped up to 17 m/min at a 5° inclination, which was then maintained. The run times were measured, and the test was ended if a rat ran more than 150 seconds.

Bottom Line: There was a significant improvement on the mechanical threshold after administration of 100, 300, and 1,000 µg gabapentin compared to pre-injection and the control group.The analgesic effect continued for 105, 135, and 210 minutes, respectively.To discern side effects, motor function was measured.

View Article: PubMed Central - PubMed

Affiliation: Department of Physical Medicine and Rehabilitation, Sun General Hospital, Daejeon, Korea.

ABSTRACT

Objective: To evaluate the analgesic effect of intrathecal gabapentin therapy on secondary hyperalgesia in a rat model of persistent muscle pain.

Methods: Intrathecal catheters were implanted into rats. Mechanical secondary hyperalgesia was induced by repeated intramuscular injections of acidic solution into the gastrocnemius muscle. Gabapentin was administrated intrathecally. Rats were allocated to control and experimental (gabapentin 30, 100, 300, and 1,000 µg) group. After gabapentin administration, mechanical withdrawal threshold was measured every 15 minutes and the motor function was measured 30 minutes later.

Results: Mechanical hyperalgesia was evoked after the second acidic buffer injection. There was a significant improvement on the mechanical threshold after administration of 100, 300, and 1,000 µg gabapentin compared to pre-injection and the control group. The analgesic effect continued for 105, 135, and 210 minutes, respectively. To discern side effects, motor function was measured. Motor function was preserved in both groups after gabapentin administration, except for rats who received 1,000 µg gabapentin.

Conclusion: Intrathecal gabapentin administration produces dose-dependent improvements in mechanical hyperalgesia in a persistent muscle pain rat model. This implicates the central nervous system as having a strong influence on the development of persistent mechanical hyperalgesia. These results are helpful in understanding the pathophysiology of secondary hyperalgesia and in the treatment of patients with chronic muscle pain.

No MeSH data available.


Related in: MedlinePlus