Definition

1. Adjective:
   • Having an effect similar to that resulting from stimulation of the parasympathetic nervous system: A parasympathomimetic substance mimics or enhances the activity of the parasympathetic nervous system, which is responsible for the body's "rest and digest" functions.

Usage

• The term is used primarily in medical, pharmacological, and physiological contexts to describe drugs or agents that produce effects such as slowing the heart rate, stimulating digestion, constricting the pupils, and increasing glandular secretions.
• It is a technical term and is not used in everyday conversation.

Examples

• Adjective:
  • Pilocarpine is a parasympathomimetic agent used to treat glaucoma.
  • The patient was administered a parasympathomimetic drug to reduce intraocular pressure.
  • These parasympathomimetic effects include bradycardia and increased intestinal motility.

Advanced Usage

• Mechanism of Action: Parasympathomimetics can work by two main mechanisms:
  • Direct Agonists: They directly stimulate the muscarinic acetylcholine receptors (e.g., pilocarpine, bethanechol).
  • Indirect Action (Cholinesterase Inhibitors): They inhibit the enzyme acetylcholinesterase, which breaks down acetylcholine, thereby increasing its availability at the synapse (e.g., neostigmine, physostigmine).

Variants and Related Words

• Parasympathomimetic (noun): A drug or substance that has parasympathomimetic properties.
  • Physostigmine is a parasympathomimetic.
• Cholinomimetic: A broader term for any agent that mimics the action of acetylcholine, which includes parasympathomimetics.
• Muscarinic agonist: A more specific term for parasympathomimetics that act on muscarinic receptors.

Synonyms

• Cholinergic: Often used interchangeably in a general sense, though "cholinergic" can refer more broadly to anything related to or mimicking acetylcholine.
• Muscarinic agent (when referring to direct agonists at muscarinic receptors).

Antonyms

• Parasympatholytic (or Anticholinergic): Having an effect that opposes or blocks the parasympathetic nervous system.
  • Atropine is a parasympatholytic drug that increases heart rate.

Adjective

1. having an effect similar to that resulting from stimulation of the parasympathetic nervous system
   • parasympathomimetic drugs slow the heart rate