From the Department of Physiology, Ghaem Medical Center, Mashhad University of Medical Sciences, Mashhad, I.R. Iran.
Abstract: (4505 Views)
The β2-adrenergic effects of macerated extract, aqueous extract, ethanol extract, and
essential oil of Carum copticum, 5 nM propranolol, and saline were tested by performing
cumulative Log concentration-response curves of isoprenaline-induced relaxation of
precontracted isolated guinea pig tracheal chains in three different conditions including:
non-incubated (group 1, n=9) incubated with 1 µM chlorpheniramine and 1 µM atropine
(group 2, n=8) and incubated with 1 µM chlorpheniramine (group 3, n=6). The effective
concentration of isoprenaline, causing 50% of maximum response (EC50), the maximum
response, and the slope of isoprenaline curves obtained in the presence of extracts,
essential oil, and propranolol were compared with those of saline.
The results showed clear leftward shifts in isoprenaline curves obtained in the
presence of only the ethanol extract compared with those of saline in group 1. In groups
2 and 3 the same finding was observed, although the effect of ethanol extract was tested
in the presence of propranolol. The EC50 and maximum response obtained in the presence
of ethanol extract were similar to those of saline in all three sets of experiments. However,
the maximum response obtained in the presence of other extracts, essential oil, and even
propranolol were lower than those for saline in all sets of experiments (p<0.05 to
p<0.001). The EC50s obtained in the presence of essential oil, macerated and aqueous
extracts, and even propranolol were greater than those obtained in the presence of saline
in the two last sets of experiments (p<0.05 to p<0.001). The maximum response obtained
in the presence of only ethanol extract in group 3 compared to group 2 was reduced
(p<0.05).
The results of this study indicate a stimulatory effect of only the ethanol extract of
Carum copticum on β2-adrenoceptors.