Asthma is a chronic airway disease that is characterized by significantly exacerbated bronchospasms and marked swelling of the airways. allergic lung tissues was identified and it was found that ()SPFF showed the highest activity among all the tested compounds, while the efficacy of (?)SPFF was similar to that of (+)SPFF. SPFF and its enantiomers stimulated cyclic adenosine monophosphate (cAMP) production in the asthmatic lung tissues examined, showing that asthmatic lung tissues had a significant cAMP enhancement in response to (?)SPFF and ()SPFF compared with (+)SPFF. Cardiac contractility of the right atria was assessed in the guinea pigs to establish the receptor selectivity of the compounds. The results indicated that all the compounds experienced high affinities to the 2 2 receptor. In conclusion, with regards to asthmatic pulmonary function improvement, (?)SPFF was more efficient when compared with (+)SPFF, while no significant difference was observed for the receptor selectivity of (?)SPFF and (+)SPFF. and the inhibition on allergy mediator launch by the various isomers of SPFF. The findings of this study may also provide a theoretical and experimental basis for further development of novel medicines for asthmatic pulmonary function. Materials and methods Chemicals and medicines (?)SPFF, ()SPFF, (+)SPFF and mabuterol (MAB) were supplied by the Pharmaceutical Engineering Division, Shenyang Pharmaceutical University (enantiomeric excess, 99%). The chemical structure of SPFF is definitely demonstrated in Fig. 1. Isoprenaline chloride was purchased from Shanghai Harvest Pharmaceutical Co., Ltd (Shanghai, China). Pentobarbital sodium and histamine phosphate were purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). Propranolol hydrochloride was obtained from the Northeast Pharmaceutical Group Co., Ltd. (Shenhe, Shenyang, China), ovalbumin (OVA) was provided by Sigma-Aldrich (Hong Kong, China) and the adsorbed diphtheria, tetanus and acellular pertussis combined vaccine were provided by the Chengdu Institute of Biological Products (Chengdu, Sichuan, China). Open in a separate window Figure 1 Molecular structure of 2-(4-amino-3-chloro-5-trifluomethyl-phenyl)-2-tert-butylamino-ethanol hydrochloride (SPFF). Animals Dunkin-Hartley male guinea pigs, weighing 30050 g, and Wistar male rats, weighing 15030 g, were provided by the Experimental Animal Centre, Shenyang Pharmaceutical University. Animals were housed in a room at a temperature of 21C23C, a relative humidity of 30C70% and a 12-h light/dark cycle with free access to food and water. All experimental procedures carried out in the study were performed in accordance with the Guidelines for the Care and Use of Laboratory Animals of Shenyang Pharmaceutical University. Konzett and R?ssler experiment in anesthetized guinea pigs The animals were randomly divided into 11 groups (n=6 per group) and anesthetized with pentobarbital [30 mg/kg, intraperitoneal injection (i.p.)]. Body temperature was maintained at 36C37C with a heating pad and the Konzett and R?ssler experiment was performed with slight modifications to an established method (6). Briefly, the trachea was cannulated and ventilated 60 times/min with a tidal air volume of 8 ml/kg using a respirator. The histamine-induced bronchoconstriction was measured using a flow transducer and recorded by a biosignal recording system. Histamine (20 g/kg) was administered intravenously 30, 60, 90, 120, 150, 180, 210 and 240 min after the intraduodenal administration of the test drugs. Histamine-induced bronchoconstriction prior to the administration of normal saline (N.S.) or the MK-2206 2HCl kinase inhibitor tested drugs was established as 100% and the inhibition rate of each bronchodilator was calculated at various time points. Effect on allergic mediator (histamine) release following an allergen challenge in rats Wistar MK-2206 2HCl kinase inhibitor rats (n=24) were sensitized by i.p. of 0.5 ml 10% OVA emulsified in 10 mg aluminum hydroxide gel in a total volume of 100 l in N.S., according MK-2206 2HCl kinase inhibitor to the method described by Kucharewicz (7) with slight modifications. Two weeks later, the animals were sacrificed by cervical dislocation and the lung tissues were removed and divided into small samples. The tissues were incubated for 5 min in 37C homothermal water. The tested drugs, in the absence and presence of propranolol (10?5 M), were added and incubated for another 5 min, and subsequently 2 mg/kg OVA was added. The production of the allergic mediator (histamine) was detected 10 min later in each sample of isolated ileum from the guinea pigs by observing the change in tension of the ileum. Determination of cyclic IKK-gamma antibody adenosine monophosphate (cAMP) levels in the lungs of OVA-sensitized rats Wistar rats were randomly divided into 12 groups (n=8). Suspensions of 100 MK-2206 2HCl kinase inhibitor mg OVA/600 mg of aluminum hydroxide in 1 ml N.S. were prepared. OVA-treated rats were sensitized by subcutaneous injection with 0.5 ml of the suspension and were also provided 0.5 ml of the same suspension by i.p. with the addition of the deactivated pertussis bacillus vaccine (5109 colony-forming units) on days 0 and 7. Non-sensitized rats received aluminum hydroxide in N.S. From day time 14, the pets had been challenged with aerosolized OVA (2% in N.S.) for 20 min a day time over seven days (8,9), and 30 min before the last OVA problem (?)SPFF, ()SPFF and.