2.4. Antispasmodic effect
Animal was killed by cervical dislocation followed by exsanguinations. Segments of jejunum about 2–2.5 cm were
suspended in oxygenated Tyrode's solution and maintained at 37 °C. It was allowed to equilibrate for at least 30 min before
the addition of any drugs. The intestinal movement and response to stimulation were recorded. A concentration response was
obtained by cumulative addition of aqueous extract. The effect of the extract against carbamylcholine chloride (carbachol,
CCH), noradrenaline (NA) at 10
−6
M, yohimbine, prazosin, propranolol at 5 10
−5
M and KCl at 40 mM was evaluated.
2.5. Statistical analysis
Student's t-test was used for statistical analysis and P< 0.05 was considered to be significant.
3. Results and discussion
The jejunum of rabbit was used to study the spontaneous basal contractions because their amplitude was easier to
evaluate than the rat jejunum. The aqueous extract of C. ladaniferus has exhibited a reversible inhibitory effect in a
dose-dependent fashion (Fig. 1).
The extract inhibited carbachol-induced contractions of jejunum of both rats and rabbit. In Fig. 2 we show only an effect
on rat jejunum. This effect tends to suggest some anticholinergic activity likely mediated through cholinergic receptors.
As envisaged we found that noradrenaline inhibits the rabbit intestinal basic contraction (Fig. 3A). The blocking of
all adrenergic receptors, α1 by the prazosin and α2 by the yohimbine and βby the propranolol, shows that
noradrenaline does not have any effect on the contractions; while the aqueous extract at the concentration of 3 mg/ml,
the dose previously shown to produce a clear antispasmodic effect, causes the inhibition of these contractions (Fig. 3B).
These results suggest that these effects were not mediated through the adrenergic receptors.
The Ca
++
plays an essential role in the cellular mechanisms regulating smooth muscle contraction [14].The
contractions induced by high K
+
depend on flux of Ca
++
into the cells through voltage dependent Ca
++
channels [15] and a
substance, which inhibits K
+
induced contractions, is considered as a calcium channel blocker. Thus, inhibition of high K
+
-
induced contractions of rabbit and rat jejunum by plant extract (Fig. 4) may be considered as an outcome of restricted Ca
++
entry via voltage dependent Ca
++
channels.
These results tend to support the ethnomedical use of these plants for the treatment of gastrointestinal disorders.
Acknowledgments
Mustapha Badraoui and Karim Ramdaoui are acknowledged for technical support and animal breeding. This work
was supported by grants from the Centre National de Recherche (CNR, Morocco), project PARS Médecine 081.
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