Spasmodic response and neurogenic mechanism of water extract of Vernonia cinerea (L.) Less. on rat duodenum

The pharmacological study was conducted on adult female albino rats (175–225g). Rats were anaesthetized with pentobarbitone sodium (40mg/kg, IP) and sacrificed by cervical dislocation and exaguination. A small piece of duodenum 4cm apart stomach was removed, cleaned and mounted on an organ bath containing Tyrode solution.The bathing fluid was continuously bubbled with air and maintained at constant temperature (37±0.5°C).The tissue was allowed to equilibrate for a period of 30min under a resting tension of 0.5 gm. During this period the tissue was washed every 15min. After equilibration, drugs were administered in bath fluid to record their effect on physiograph. Every time responses of 2 successive doses of acetylcholine (ACh), at an interval of 10min were recorded to confirm optimum responsiveness of the tissues. Serial solutions of the water extract of Vernonia cinerea (L.) Less. whole plant (VWE) were prepared directly in Tyrode solution and mixed properly with the help of an Ultra-Sonicator. Effect of cumulative doses (0.25 to 25mg/ml) of VWE on rat duodenal smooth muscle was recorded. This response indicates that the plant contains an active ingredient, which has spasmogenic response on rat duodenal smooth muscle. The responses of VWE were fully reversible on wash. This finding suggests that VWE's responses were mediated through an agonistic action without blockade of any receptor or enzyme. Extract possibly stimulates presynaptic cholinergic nerve endings to produce spasmodic response in rat duodenal smooth muscle.

Keywords: Vernonia cinerea, Rat duodenum, Aqueous extract, spasmodic response

Acknowledgement: Thanks are due to authorities of G.B. Pant University of Agriculture & Technology, Pantnagar, India for providing necessary research facilities.