Tag: Parasympathetic nervous system

As an anticholinergic drug, atropine's primary mechanism involves inhibiting the parasympathetic nervous system, which can slow gastrointestinal motility [1.4.4, 1.2.1]. The central question for many patients is, **does atropine cause constipation** as a result of this action? The answer lies in its pharmacological effects.

**Fact:** The iris sphincter muscle contains muscarinic acetylcholine receptors, and stimulating them is the specific mechanism by which **cholinergics constrict pupils**. This action, known as miosis, is a key function of the parasympathetic nervous system.

Pharmacological studies have unequivocally established that muscarinic antagonists cause pupil dilation, a process known as mydriasis. These anticholinergic drugs are essential tools in ophthalmology, used to enlarge the pupil for diagnostic eye examinations and therapeutic purposes. This effect is a direct result of inhibiting the parasympathetic nervous system's control over the eye's iris muscles.

Discovered in 1874, pilocarpine is a long-standing cholinergic agonist whose mechanism of action centers on stimulating specific receptors in the body. To understand what pilocarpine acts on, one must first grasp its interaction with the muscarinic acetylcholine receptor family, which mediates a wide range of parasympathetic responses.

Glycopyrrolate is a synthetic anticholinergic agent that inhibits the action of acetylcholine on glands and smooth muscles throughout the body. As a competitive inhibitor of muscarinic acetylcholine receptors, glycopyrrolate reduces various bodily secretions, offering therapeutic effects for conditions like excessive sweating, drooling, and certain respiratory diseases.

First-line treatment for symptomatic bradycardia often involves atropine. The mechanism of action of atropine to increase heart rate centers on its role as an anticholinergic agent, effectively blocking the parasympathetic nervous system's 'braking' effect on the heart.

The human body's 'rest and digest' functions are primarily controlled by the parasympathetic nervous system, with acetylcholine being its chief neurotransmitter. Cholinergic drugs are a class of medications that target this system by enhancing or mimicking the action of acetylcholine. This article explains what these drugs are, their mechanisms, and their important therapeutic applications.

Did you know that the dilation of your pupils during an eye exam is often caused by anticholinergic medication? This temporary effect, known as mydriasis, is a classic pharmacological action of these drugs, which specifically target and disrupt the eye's intricate involuntary muscle control system.

The classic mnemonic for anticholinergic toxicity includes the phrase “blind as a bat,” which refers to the resulting pupil dilation. This visual side effect, known as mydriasis, reveals precisely **how do anticholinergic drugs affect the pupils**, by disrupting the body's involuntary control over the iris muscles.

Worldwide, organophosphate poisoning—a major cause of severe cholinergic side effects—affects millions of people annually, with a high mortality rate without swift medical intervention. A cholinergic side effect is the result of overstimulating the body's cholinergic system, which can range from minor discomfort to life-threatening emergencies.