Steric aspects of formoterol and terbutaline: Is there an adverse effect of the distomer on airway smooth muscle function?
✍ Scribed by Britt-Louise Källström; Jacob Sjöberg; Bertil Waldeck
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 619 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0899-0042
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✦ Synopsis
Experiments were made on isolated tissues from guinea-pig to test the hypothesis that the distomers of rac-Pzadrenoceptor agonists induce airway hyperreactivity. Tracheal strip preparations were contracted with carbachol. Both racand (RR)-formoterol (2 and 1 kmol/l, respectively) produced an immediate relaxation, followed by a slow recovery of tone. (3s)-Formoterol (2 kmol/l) had no effect on smooth muscle tone. Similar results were obtained with the enantiomers of terbutaline. In other strip preparations of the trachea or the main bronchi, cholinergic or nonadrenergic/noncholinergic (NANC) excitatory responses were evoked by electrical field-stimulation. The eutomers, (R;R)-formoterol and (R)-terbutaline, inhibited concentration-dependently both cholinergic and NANC-induced contractions. The distomers, (S;S)-formoterol and (S)-terbutaline, showed qualitatively the same effects but were about 1,000 times less potent than the corresponding eutomer. In a third series of experiments, either enantiomer of formoterol was administered to an electrically stimulated
Animals and General Experimental Procedure
Male Dunkin-Hartley guinea-pigs (Msllegaard, Denmark), weighing 200-400 g, were anaesthetized with pentobarbitone and exsanguinated by cutting the subclavian arteries. The trachea and the main bronchi, with or without the adhering vagus