| Objective:1. To determine the effect of Rhizoma Curcumae (RC) on the spontaneous contraction of murine colonic smooth muscle strips in vitro and to investigate its possible mechanism.2. To determine the effect of Areca Seed (AS) on the spontaneous contraction of murine colonic smooth muscle strips in vitro and to explore its possible mechanism.3. To observe the effect of Dimethyl Sulfoxide (DMSO) on colonic smooth muscle strips of rats in vitro and to find the range of concentration meeting the requirements of solvents with no significant influence on the activity of colonic smooth muscle strips of SD rats.Methods:1. The colonic longitudinal smooth muscle strips of rats were suspended in issue chambers containing 10ml Krebs solution at 37℃and their spontaneous contractions. First, we observed the effects of RC and AS on the spontaneous contraction of colonic smooth muscle strips using sodium chloride ( 9 g/L ) (NS) as control. We also investigated the impacts on RC and AS induced contraction of three different antagonists, Verapamil, Phentolamine and Atropine, respectively with RC or AS alone as control.2. Colonic smooth muscle strips of SD rats were prepared in the same way mentioned above. The effects of DMSO on the spontaneous contraction and the Ach-induced contraction of muscle strips were observed with NS treated sample as control group. Results:1. In the study, RC showed dose-dependent promotive effects on the spontaneous contraction of colonic muscle strips in vitro at the concentration of 0.01-10g/L. Peak and Area of Ach-induced contraction were referred to as 100% here. For both the Peak and the Area, RC 1g/L group ( Peak=63.92%±2.06%, P=0.0001; area=44.09%±11.10%, P=0.043) and RC 10g/L group ( Peak=76.27%±2.28%, P=0.0001; area=55.66%±10.29%, P=0.001) exhibited significant difference from the NS group ( P < 0.05 ). While the results of RC 1g/L ( Peak=48.95%±4.91%, P=0.961; Area=29.76%±12.91%, P=0.994 ) group and RC 10g/L group ( Peak=50.23%±4.04% , P=0.523; Area=30.82%±10.66%, P=0.881 ) were similar to NS control group. In order to investigate the action mechanism of RC on the contraction of colonic smooth muscle strip, the impacts of three antagonists, verapami, atropine and phentolamine were observed respectively. Peak and Area of contraction induced by RC 10g/L were referred to as 100% in this experiment. The Peak and Area values of verapami + RC group ( Peak=87.35%±50.49%, P=0.016; Area=73.80%±9.37%, P=0.001 ) and atropine+RC group ( Peak=33.97%±15.18%, P=0.001; Area=27.55%±11.56%, P=0.0001 ) shrank considerably compared with RC 1000g/L group ( P<0.05 ). While phentolamine + RC group ( Peak=98.85%±3.819%, P=0.812; Area=98.67%±3.61%, P=0.767 ) showed comparable results as RC 10g/L group. It was found that the peak value and area of contraction curve of smooth muscle strips induced by RC 10g/L were significantly inhibited with incubation of Atropine and Verapami ( P < 0.05 ), but there was no significant difference in Phentolamine group.2. AS showed dose-dependent promotive effects on the spontaneous contraction of colonic muscle strips in vitro at the concentration of 0.01-10g/L. Peak and Area of the Ach-induced contraction were referred to as 100% here. For both the Peak and the Area of contraction curve, AS 0.1g/L group ( Peak=81.62%±7.03%, P=0.019; Area=68.16%±12.56%, P=0.002 ), AS 1g/L group ( Peak=106.52%±26.93%, P=0.0001; area=151.07%±27.78%, P=0.0001 ) as well as AS 10g/L group ( Peak=122.11%±26.75%, P=0.0001; Area=222.32%±24.54%, P=0.0001) showed meaningful different results compared to the NS group ( P < 0.05 ). No significant difference was observed between AS 0.01g/L group ( Peak=63.53%±19.87%, P=0.303; Area=41.80%±11.04%, P=0.334) group and NS group. In the experiment to observe the effects of three different antagonists on AS-induced contraction, Peak and Area of contraction induced by AS 1g/L were referred to as 100%. It was observed that Verapami + AS group ( Peak=74.03%±9.49%, P=0.0001; Area=73.10%±11.92%, P=0.0001 ) and the Atropine + AS group ( Peak=12.77%±9.98%, P=0.0001; Area=11.45%±8.54%, P=0.0001) exhibits decreased results compared to AS 1g/L group ( P < 0.05 ). While the Phentolamine +AS group ( Peak=101.32%±5.90%, P=0.764; Area=98.16%±3.41%, P=0.676) showed comparable results as RC 10g/L group. It illustrated that Atropine and Verapami imposed significant inhibitory effects on the contraction of smooth muscle strips induced by AS 1g/L, but there was no similar findings in Phentolamine group.3. It was observed that within 0.2% ~ 1.4% (V/V), the DMSO had no considerable influence on the amplitude and area of the spontaneous contraction of colonic smooth muscle strips of rats. Data was shown below: DMSO 0.2% group 99.99%±0.08% ( P=1.000 ),0.4% group 100.04%±0.17% ( P=1.000 ),0.6% group 100.11%±0.15% ( P=0.958 ),0.8% group 99.94333±0.61% ( P=1.000 ),1.0% group 99.94%±1.79% ( P=1.000 ),1.4% group 88.225%±5.34% ( P=0.086 ). DMSO 1.8% group 72.93%±7.63% ( P=0.011 ),2.2% group 67.87%±12.18% ( P=0.043 ),2.6% group 65.26%±11.02% ( P=0.019 ),3.0% group 57.80%± 12.70% ( P=0.015 ),3.4% group 47.33%±10.65% ( P=0.002 ),3.8% group 39.34%±12.87% ( P=0.003 ),4.2% group 33.45%±9.61% ( P=0.001 ),4.6% group 32.18%±8.25% ( P=0.001 ),5.0% group 24.05%±8.78% ( P=0.001 ),5.4% group 22.70%±8.57% ( P=0.001 ) , 5.8% group 16.83%±7.52% ( P=0.001 )。Also no significant influence was observed imposed by DMSO on the Ach-induced contraction within 0.2% ~ 1.8% (V/V) concentration range. Data was shown below: DMSO 0.2% group 100%±0.01% ( P=1.000 ),0.4% group 100.00%±0.09% ( P=1.000 ),0.6% group 100.03%±0.41% ( P=1.000 ),0.8% group 100.03%±0.38% ( P=1.000 ),1.0% group 99.92%±0.50% ( P=1.000 ),1.4% group 96.70%±3.55% ( P=0.814 ),1.8% group 83.90%±7.41% ( P=0.091 ),2.2% group 76.86%±8.37% ( P=0.034 ),2.6% group 60.71%±9.46% ( P=0.006 ),3.0% group 55.29%±14.04% ( P=0.018 ),3.4% group 62.32%±18.73% ( P=0.012 ),3.8% group 46.81%±13.33% ( P=0.007 ) , 4.2% group 39.57%±7.96% ( P=0.001 ),4.6% group 36.53%±11.29% ( P=0.001 ),5.0% group 29.59%±9.67% ( P=0.001 ),5.4% group 17.23%±9.03% ( P=0.001 ),5.8% group 11.58%±7.44% ( P=0.001 ).Conclusion:1. RC showed promotive effects on spontaneous contraction of murine colonic smooth muscle strips in vitro. Its possible promotive mechanism has close relations with the calcium and perhaps with the M-cholinergic receptor, but has little relation with theα-adrenoceptor receptor.2. AS showed promotion effects on spontaneous contraction of murine colonic smooth muscle strips in vitro. It is possible promotive mechanism may involve the action of calcium and perhaps the M-cholinergic receptor, but has little relation with theα-adrenoceptor receptor.3. Our study indicated that DMSO below the concentration of 1.4% ( V/V ) had no apparent effects on the contraction activity of colonic smooth muscle strips of SD rats. So DMSO can be used as cosolvent in study of fat-soluble traditional Chinese medicine. |
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