Pharmacological Evaluations for the Relaxant Effect of the Hydroalcoholic Extract of Tapinanthus dodoneifolius on Rat Trachea

Abstract

The present study was designed to investigate the blocking of calcium by the hydroalcoholic extract of Tapinanthus dodoneifolius (Tapidod), \"in vitro\", on rat trachea. To evaluate this effect, the contractile activity of tracheal chains from Wistar Kyoto rats was isometrically recorded. On the isolated tracheal rings the extract produced the following effects: (a) a reduction of the contraction obtained by BaCl₂, (b) a bronchorelaxing action, on strips precontracted by KCl, which was not influenced by TEA (3x10^-3 M), (c) a concentrationdependent decrease of the spasm evoked by calcium chloride (CaCl₂) in K⁺ -rich Ca²⁺ -free physiological salt solution, before and after intracellular calcium depletion (d), an inhibitory effect on contraction induced by acetylcholine in Ca²⁺ -free Krebs-Heinseleit solution supplemented with EDTA (5x10^-4M). It is concluded that: 1. The activation of the potassium channels does not play a significant role in the relaxant effect of Tapidod. 2. The antispasmodic property of Tapidod seems to be mediated by the blockade of intracellular Ca²⁺ release. 3. Most likely an inhibition of the intracellular Ca²⁺-regulating proteins is involved.

Key Words: Extract of Tapinanthus dodoneifolius (Tapidod); Trachea; Calcium.

Afr. J. Trad. CAM (2005) 2 (2): 166-176