TY - JOUR T1 - STIMULATORY EFFECT OF NIGELLA SATIVA ON β2-ADRENOCEPTORS OF GUINEA PIG TRACHEAL CHAINS TT - JF - MJIRI JO - MJIRI VL - 18 IS - 2 UR - http://mjiri.iums.ac.ir/article-1-636-en.html Y1 - 2004 SP - 153 EP - 158 KW - Nigella sativa KW - adrenergic effect KW - trachea KW - guinea pig N2 - Our previous studies have demonstrated the relaxant, anticholinergic (functional antagonism), antihistaminic, and inhibitory effect of calcium channels of Nigella sativa on guinea pig tracheal chains. To investigate the other mechanism responsible for the relaxant effect of this plant, the stimulatory effect of Nigella sativa on J32-adrenergic receptors in tracheal chains of the guinea pig was examined in this study. The 􀁫2-Adrenergic effects of macerated and aqueous extracts from Nigella sativa, 50 nM propranolol, and saline were tested by performing the cumulative Log concentration-response curves of isoprenaline induced relaxation of precontracted isolated guinea pig tracheal chains with three different conditions including: non-incubated (group 1, n=8) incubated with I ).lM chlorpheniramine, and 1 ).lM atropine (group 2, n=5). The effective concentration of isoprenaline, causing 50% of maximum response (ECso)' maximum response and the slope of isoprenaline curves obtained in the presence of extracts, and propranolol were compared with those of saline. The results showed clear leftward shifts in isoprenaline curves obtained in the presence of both macerated and aqueous extracts compared with that of saline in group 2. The EC50 obtained in the presence of aqueous extract in group 2 was significantly lower than that of saline (p M3 ER -