Complex sentence: Although it does not display selectivity for specific muscarinic receptors, on topical application it acts mainly on M 3 muscarinic receptors located on smooth muscle cells and submucosal glands leading to a reduction in smooth muscle contraction and mucus secretion, thus producing a bronchodilatory effect.
Split into simpler sentences: Although it does not display selectivity for specific muscarinic receptors, when topically applied it acts mainly on M 3 muscarinic receptors located on smooth muscle cells and submucosal glands. This leads to a reduction in smooth muscle contraction and mucus secretion and thus produces a bronchodilatory effect.