Effects of Dangshen on isolated gastric muscle strips in rats.

AIM:To study the effects of Dangshen dried root of Codonopsis Pilosula (Franch) Nannf on contractile activity of isolated gastric muscle strips in rats and its possible mechanism involved.

METHODS

Each isolated gastric muscle strip was put in a tissue chamber containing 5ml Krebs solution, constantly warmed by water jacket at 37?mgr; and supplied with a mixed gas of 95% O(2) and 5% CO(2). After incubating for 1h with 1g tension, Dangshen of varied concentration was added cumulatively in the tissue chamber at intervals of 2 minutes. The isometrical response was measured on ink-writing recorders.

RESULTS

Dangshen dose dependence increased the resting tension of longitudinal muscle (LM) of fundus (r =0.96, P < 0.01), the mean contractile amplitude of circular muscle (CM) of the stomach body (r =0.87, P < 0.05) and CM of antrum (r =0.98, P < 0.01), and the motility index CM of pylorus(r =0.87, P < 0.05). Atropine (5 10( 8)mol/L) or Hexamethonium (10( 5)mol/L) or Indomethacin (5 10( 7)mol/L) was given 2 minutes before the administration of Dangshen, it did not abolish its dose related manner. Atropine apparently reduced the increasing action of 10% and 30% Dangshen on the resting tesion of LM of fundus (P < 0.05), 30%, 100% and 200% Dangshen on bodied strips (P < 0.05), 100% and 200% Dangshen on antral strips (P < 0.05).Hexamethonium reduced the increasing action of 10% and 30% Dangshen on the resting tesion of LM of fundus (P < 0.05 and P < 0.05), 30%, 100% and 200% Dangshen on bodied strips (P < 0.05), and 100% and 200% Dangshen on pyloric strips (P < 0.05). Indomethacin inhibited the effect of 10% Dangshen on the resting tesion of LM of fundus (P < 0.05), but did not affect the exciting action of Dangshen on strips of body, antrum and pylorus.

CONCLUSION

The results showed that Dangshen possessed exciting action on the isolated gastric smooth muscle strips of the rat.The exciting action of Dangshen was partially mediated via cholinergic M and N receptors.