Lack of correlation between plasma asymmetric dimethylarginine (ADMA) levels and pain-related behaviors in neuropathic rats

ObjectivesRecent research has demonstrated elevations of ADMA levels in many cardiovascular and metabolic diseases, and ADMA has also been proposed as a modulator of nociception in opiate tolerance and addiction. The present study was conducted to determine whether increased level of peripheral ADMA is implicated in tactile allodynia in rats with partial tight ligation of the sciatic nerve.MethodsBeginning from the 1st measurement after the ligation, paw withdrawal thresholds significantly reduced compared with duration-matched control animals, indicating that mechanical allodynia developed in sciatic nerve-ligated rats.ResultsIn both neuropathic and control groups, plasma levels of ADMA, SDMA, l-homoarginine and l-arginine remained unchanged throughout the experiment, and there were no significant differences between two groups in different durations.ConclusionThese results suggest that endogenous plasma ADMA, SDMA, l-homoarginine and l-arginine levels do not change during the different stages of neuropathic duration, and accordingly may not be implicated in tactile allodynia in neuropathic rats.

► ADMA has been proposed as a modulator of nociception in opiate tolerance and addiction.
► We examine whether peripheral ADMA levels is implicated in tactile allodynia.
► Plasma levels of ADMA remained unchanged in neuropathic rats.
► Endogenous plasma ADMA may not be implicated in tactile allodynia in neuropathic rats.