Sheng Li Xue Bao. 1994 Aug; 46(4): 313-9.

[The potentiation effect of haloperidol on the binding of etorphine to brain membranes in acupuncture analgesia]

Wang HH, Zhu YH, Xu SF.

Department of Neurobiology, Shanghai Medical University.

[3H]-etorphine was used in receptor binding studies on membrane preparation from rabbit brain. Scatchard analysis revealed that rabbit brain had two different affinity binding sites. In the high affinity site, the dissociation constant (Kd1) of the control group was 2.57 +/- 0.33 nmol/L. When analgesia was induced by haloperidol or acupuncture, the Kd1 values decreased respectively (P < 0.05) to 1.44 +/- 0.03 nmol/L and 1.53 +/- 0.05 nmol/L. These Kd1 values further decreased to 1.25 +/- 0.03 nmol/L when acupuncture analgesia was potentiated by combined action of acupuncture and i.v. haloperidol (P < 0.01). In case of autoradiographic analysis of brain slices showed that the density of opioid receptors in many brain regions, such as N. Caudatus, preoptic lateral area, N. Paraventricularis, N. Centromedianus, Periaqueductal gray, showed significant increase, a results indicating that the upregulation of opioid receptors in rabbit brain may be one of the mechanisms in the potentiating action of haloperidol on acupuncture analgesia.