Laxative effect of cassia senna : single and double sucrose-gap studies on locustae migratoria foregut visceral muscles

الملخص EN

The locust foregut and hindgut K+-contractions were inhibited by aqueous extract of sienna.

This inhibitory action was dose-dependent and stronger in foregut than hindgut muscles.

In single sucrose-gap method, isotonic KCl saline depolarized the foregut muscle in the right chamber up to 6-8mV and 4-6mV in the left chamber followed with a slight contraction.

Adding sienna extract alone depolarized the muscle up to 0.3 mV, followed by a hypo-polarization up to 0.5 mV, and was accompanied by a drop in the base line tension.

Addition of 10-5 M 5-HT, depolarized the foregut muscle up to 1 mV accompanied with a slight contraction.

In the double sucrose-gap method, 100 mMK + induced an inward current of about 0.3 IlA without any increase in tension.

Addition of sienna extract alone induced an outward current of about 0.02 IlA accompanied with drop in base line tension.

Pre-treatment with sienna extract for 10 minutes induced very small outward current, while K+ in presence of sienna induced inward current of about 0.15 IlA but no clear tension was recorded.

However, addition of 5-HT (10-5M) alone induced an outward current up to 0.07 IlA accompanied by a drop in the base line tension.

Pre-treating the gut with sienna extract for 10 minutes prior to 5-HT (10-5 M) induced an outward current of about 0.05 IlA accompanied by a drop in the base line tension. Upon returning to initial control after washing, 100mM K + induced an inward current of about 0.2 IlA but no muscle response was recorded.

The depolarization induced by 100mM K + may release bound cellular Ca2+ needed for contraction, or it may even mobilise different cellular Ca2+-stores.

Results reported in this study suggest that sienna inhibited the 5-HT activity in a reversible manner probably through binding with the serotonin receptors, and that sienna may cause an inhibition of ionic exchange through cell membrane or alteration in electrolyte influx and efflux thus acting as a laxative.