Effects of intrathecal anandamide on somatosensory evoked responses in rats

• Published in: Experimental neurology 2006-02, Vol.197 (2), p.386-390
• Main Authors: Sinan Bir, Levent, Ercan, Sevim
• Format: Article
• Language: English
• Subjects: Anandamide; Animals; Arachidonic Acids - pharmacology; Biological and medical sciences; Cannabinoid Receptor Modulators - pharmacology; Cannabinoids; Central nervous system; Dose-Response Relationship, Drug; Electrodiagnosis. Electric activity recording; Electroencephalography; Endocannabinoids; Evoked Potentials, Somatosensory - drug effects; Injuries of the nervous system and the skull. Diseases due to physical agents; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Nervous system; Polyunsaturated Alkamides; Rats; Rats, Wistar; Reaction Time - drug effects; Sensorial pathways; Somatosensory Cortex - drug effects; Somatosensory evoked potentials; Statistics, Nonparametric; Traumas. Diseases due to physical agents
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2005.10.010

Anandamide, endogenous ligand of cannabinoid receptors produces similar effects of cannabinoids via CB1 receptors in the central nervous system. Its effect on ascending pathways of somatosensory conduction and somatosensory cortex is not known. The aim of this study was to determine the effects of anandamide on somatosensory evoked potentials (SEP). In this study, 24 Wistar male rats were used. The rats were divided into 4 groups. At the beginning, sciatic nerve stimulated scalp SEP traces were obtained from all of the rats. Later, 0.02 cm 3 anhydrous ethanol, 100 μg/kg, 200 μg/kg and 400 μg/kg anandamide dissolved in anhydrous ethanol were injected intrathecally to the first (control), second, third and fourth groups, respectively. Five minutes later, second SEP traces were started. In every SEP trace, two negative waves (N1, N2) following positive deflections were obtained. The latency and amplitudes of these waves assessed were compared in each group. In control and second groups, the parameters of these waves before and after the injections were not significantly different. However, in the third and fourth groups, latencies of N1 and N2 after injections were found significantly longer. This effect was dose dependent. In any of the groups, no significant changes were detected in the amplitudes after injections. In conclusion, anandamide, when injected intrathecally in pharmacological doses caused an induction of moderate conduction delay in SEP systems.