Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
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Rotundine is an active alkaloid isolated from the stem tubers of the Chinese medicinalRotundine is an active alkaloid isolated from the stem tubers of the Chinese medicinal herb Corydalis sp. It is the l-optical isomer of tetrahydropalmatine. The present study determined effects of rotundine on tolerance, and physical and psychic dependence in animal models. The analgesic effect of morphine was determined by a mouse hot-plate test in female mice. The analgesic effect of morphine was reduced by chronic morphine injection, indicating the development of tolerance. Rotundine at 20 mg/kg given subcutaneously (s.c.), which by itself did not produce any antinociceptive effect, significantly inhibited the development of tolerance. The physical dependence was evaluated in male rats. The behavioral signs including jumping, wet-dog shakes, teeth chattering, writhing, diarrhea, ptosis and vocalizing on touch, were observed. Withdrawal was precipitated by a single injection of naloxone in dependent rats. Rotundine (20 mg/kg, s.c.) suppressed jumping, teeth chattering, diarrhea and irritability but not other signs of physical dependence in the rat. The psychic dependence was assessed by the conditioned place preference in male mice. Rotundine (20 mg/kg s.c.), significantly attenuated the place preference induced by morphine. The results suggest that rotundine may be a useful drug for suppressing morphine tolerance and withdrawal symptoms. (Supported by Faculty of Medicine, HKU and National Natural Science Foundation of China (39570810)).

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Presentation Number SAwong0190
Keywords: rotudine, morphine, tolerance, dependence, withdrawal