Sheng Li Xue Bao. 1998 Feb; 50(1): 43-8.
[Effect of intrathecal injection of dopamine receptor agonists/antagonists on pain and acupuncture analgesia in rats]
State Key Laboratory of Medical Neurobiology, Shanghai Medical University, Shanghai 200032.
Some selective dopamine receptor agonists and antagonists were tested on rat tail flick model to investigate the role of D1 and D2 dopamine receptor in pain and acupuncture analgesia (AA). It was found that intrathecal administration (i.t.) of D2 receptor agonist LY171555 or D1/D2 receptor agonist apomorphine increased pain threshold and had a potentiating effect on AA. In contrast, D1 receptor agonist SKF38393 had no effect. It D1 receptor antagonist SCH23390 or D2 receptor antagonist sulpiride attenuated the effect of AA. The results suggest that D2 receptor is involved in pain modulation and activation of D2 receptor and enhances AA in the spinal cord, while such effect is absent in D1 receptor and inactivation of D1 receptor attenuates AA.