Final answer:
The correct action and clinical use of muscarinic cholinoceptor agonists is the improved drainage of aqueous humor for treating glaucoma, such as when using pilocarpine. This drug contracts the ciliary muscle, facilitating the drainage of aqueous humor and reducing intraocular pressure.
Step-by-step explanation:
Actions and Clinical Uses of Muscarinic Cholinoceptor Agonists. Among the actions and clinical uses of muscarinic cholinoceptor agonists, the correct option includes improved aqueous humor drainage in the treatment of glaucoma. Pilocarpine is an example of such an agent, which reduces intraocular pressure by causing the ciliary muscle in the eye to contract, thus enhancing the drainage of aqueous humor through perforations at the base of the cornea. Other options, such as bronchodilation and decreased gastrointestinal motility, are associated with different classes of drugs or the opposing actions of muscarinic antagonists.
For instance, muscarinic agonists typically do not cause bronchodilation in asthma treatments; rather, beta-2 adrenergic receptor agonists are employed for this purpose. Moreover, muscarinic agonists are known to increase gastrointestinal motility, not decrease it, which is a characteristic counter to the choice of treating diarrhea. As for muscular relaxation during surgical anesthesia, that is an effect of neuromuscular blocking agents, not muscarinic agonists.