How is Ach as direct acting cholinergic agonist?

Quaternary amonium, cannot penetrate membranes, not very important since cholinesterase rapid inactivation. Decreases HR and CO (negative chronotropy), Decreases BP (activates M3 receptors of endothelia cause vasodilation), Increases saliva and intestinal secretion and motility, bronchiolar increased secretions, expulsion of urine increasing tone of detursor muscle, stimulate ciliary muscle contration for near vision, contraction of sphincter for miosis.