Tag: Muscarinic receptors

The parasympathetic nervous system plays a vital role in regulating airway tone, and its key neurotransmitter, acetylcholine, is a potent bronchoconstrictor. This confirms that, yes, cholinergics cause bronchoconstriction by triggering a specific chain of events that leads to the contraction of airway smooth muscle.

For over 30 years, there have been no new classes of medication for treating psychosis, a long-standing challenge for patients and clinicians. The recent FDA approval of Cobenfy, formerly KarXT, marks a significant milestone by introducing a novel mechanism to address the complex symptoms of psychosis. This provides a new answer to the question, **what is the new drug for psychosis?**

According to prescribing information, oral pilocarpine can cause side effects related to increased parasympathetic activity, including vasodilation. This article explores the pharmacological basis for why pilocarpine causes vasodilation, examining the distinct effects of systemic versus topical administration.

A 2025 study on young adults showed a single drop of atropine, even in low concentrations, significantly increased pupil diameter within an hour. This fact immediately contradicts the idea that atropine constricts the pupil, as its primary ophthalmic function is to cause dilation. The medication works by blocking specific receptors in the eye that control pupil size, leading to widening, also known as mydriasis.

Studies show that up to 50% of older adults are prescribed drugs with anticholinergic effects [1.7.3]. As an atypical antipsychotic, understanding how anticholinergic is olanzapine is crucial for managing its side effect profile, which includes both peripheral and central effects [1.4.2].

The human body's parasympathetic nervous system controls numerous involuntary functions, from digestion to urination, primarily using acetylcholine as its neurotransmitter [1.2.1, 1.2.2]. The central question for many is, do cholinergics constrict tissues, and what are the widespread implications of this action?

Atropine has been a first-line treatment for symptomatic bradycardia in many emergency settings for decades. But **why does atropine work for bradycardia**? The answer lies in its ability to effectively counteract the parasympathetic nervous system's inhibitory influence on the heart's natural rhythm.

Discovered in 1914, acetylcholine (ACh) was the very first neurotransmitter to be identified [1.5.3]. Understanding **what is the mechanism of action of acetylcholine?** is fundamental to grasping how our nervous system controls everything from muscle movement to memory [1.5.3, 1.5.5].

Did you know that atropine, a medication derived from the deadly nightshade plant, has a long-standing history as a first-line treatment for an abnormally slow heart rate, or bradycardia? This anticholinergic drug plays a critical role in emergency medicine by addressing certain cardiac rhythm disturbances, but to truly grasp **what is the role of atropine in the heart**, one must understand its mechanism of action within the autonomic nervous system.

Cyclopentolate is a powerful mydriatic and cycloplegic, with maximal cycloplegia occurring within 25 to 75 minutes of instillation. This anticholinergic agent is widely used in ophthalmology for eye examinations, working by blocking specific receptors in the eye's muscles.