Karch Chapter 32: Cholinergic Agonists

This set of vocabulary flashcards covers key terms, pharmacological prototypes, mechanisms of action, and physiological comparisons related to cholinergic agonists as presented in Karch Chapter 32.

Cholinergic Agonist

A substance that stimulates ACh receptors to mimic parasympathetic activity; also known as a parasympathomimetic.

Direct-acting agonists

Agents that bind directly to cholinergic receptors and activate them.

Indirect-acting agonists

Agents that inhibit acetylcholinesterase, thereby increasing acetylcholine levels at the synapse.

Muscarinic Receptors

Cholinergic receptors found in smooth muscle, glands, and the heart that mediate most therapeutic effects.

Nicotinic Receptors

Cholinergic receptors found at neuromuscular junctions and autonomic ganglia.

Parasympathomimetic

Another term used to describe a cholinergic agonist.

SLUDGE Syndrome

An acronym for the adverse effects of cholinergic stimulation: Salivation, Lacrimation, Urination, Diarrhea, GI cramps, and Emesis.

Acetylcholinesterase (AChE)

The enzyme responsible for the breakdown of acetylcholine into choline and acetic acid.

Bethanechol

A prototype direct-acting muscarinic agonist used to treat non-obstructive urinary retention and neurogenic bladder; onset is $30-90\,\text{min}$ with a duration of $1-6\,\text{hrs}$.

Varenicline

A prototype direct-acting nicotinic agonist and partial agonist used for smoking cessation; it has a peak of $3-4\,\text{hrs}$ and a half-life of $24\,\text{hrs}$.

Pyridostigmine

A prototype indirect-acting cholinergic agonist used for Myasthenia Gravis and the reversal of neuromuscular blockers; typically has an oral onset of $35-45\,\text{min}$.

Donepezil

An indirect-acting cholinergic agonist used as a prototype agent for the treatment of Alzheimer’s Disease.

Atropine

The specific antidote that should be kept available for the treatment of cholinergic overdose or crisis.

Sympathetic Nervous System CNS origin

The thoracic and lumbar regions of the spinal cord.

Parasympathetic Nervous System CNS origin

The cranium and sacral region of the spinal cord.

Sympathetic Preganglionic Neuron

Characterized by having a short axon that uses acetylcholine (ACh) as a neurotransmitter.

Parasympathetic Preganglionic Neuron

Characterized by having a long axon that uses acetylcholine (ACh) as a neurotransmitter.

Sympathetic Postganglionic neurotransmitter

Primarily norepinephrine and epinephrine.

Parasympathetic Postganglionic neurotransmitter

Acetylcholine (ACh).

MAO and COMT

The terminators for neurotransmitters within the sympathetic nervous system.