The effects of cholecystokinin octapeptide (CCK-8) and its selective antagonists (proglumide, MK-329) on morphine induced analgesia (MIA) in the paw pressure test of the Wistar-SPF male rats were investigated. Baseline pain thresholds indicated that the morning (09:00-12:00) testing were significantly higher than the afternoon (14:00-18:00) testing. This result supports that diurnal variation of endogenous opioids. MIA was shown clear (p<0.01) dose-dependent (1.5-15mg/kg, i. p., n=6) manner with significant correlation coefficient (y=3.98x+22.67, r=0.827, p<0.001). CCK significantly (p<0.01) reduced MIA. Both proglumide (5-50mg/kg) and MK-329 (0.5-5.0mg/kg) were enhanced MIA. Especially, MK-329 has shown potently enhanced MIA. i. e. it showed desinhibition to the CCK's inhibitory action to MIA. These results suggest that CCK play important role to the endogenous opioids antagonist via through CCK-B receptors and to the function of the pain/analgesic mechanisms.

We have investigated that individual properties and irritability to the electrical stimulation of Wenliu (Li-7) were determined by acupuncture of Hegu (Li-4) and Quchi (Li-11) as the strength-duration relations.
Results showed that reobase (27.8±1.09V, n=114), utilization time (1.38±0.13ms, n=114) and chronaxie (0.031±0.002ms, n=114), were interestingly similar as previous results of in vitro studies.
Value of chronaxie of female subjects (0.021±0.001ms, n=21) was significantly lower than male (0.053±0.010ms, n=36). So that acupuncture stimulation influenced to the chronaxie.
Hegu stimulation significantly (p<0.05) shortend than Quchi stimulation as compared to intact control group.
These results might be suggested that it has to considered responses to stimulation in the sex differences when determination of acupuncture effects in the clinical and/or research studies.