Autonomic Nervous System Drugs

Question 1

Two Main Parts of the Nervous System

Answer 1

Central Nervous System which is made up of the brain and spinal cord and Peripheral Nervous System which is made up of nerves that branch off from the spinal cord and extend to all parts of the body.

Question 2

Neurons that send impulses to the central nervous system

Answer 2

Afferent Neurons

Question 3

Neurons that receive impulses and transmit them through the spinal cord to effector organ cells.

Answer 3

Efferent Neurons

Question 4

Acetylcholine

Answer 4

Preganglionic neurotransmitter for both sympathetic and parasympathetic nervous system.

Question 5

Norepinephrine

Answer 5

Postganglionic neurotransmitter for sympathetic nervous system only.

Question 6

Autonomic Nervous System vs. Somatic Nervous System

Answer 6

Autonomic Nervous System controls involuntary movements, can regulate the heart, GI, respiratory system, bladder, and glands, majority of the organs are supplied by both sympathetic and parasympathetic nerves.

Somatic Nervous System is responsible for voluntary movements, usually innervates the skeletal muscle, and includes both afferent and efferent neurons.

Question 7

Five Step of Synaptic Transmission

Answer 7

Step 1: Synthesis
Step 2: Storage
Step 3: Release of the Neurotransmitter
Step 4: Action at the receptor
Step 5: Termination of the transmission
5.a. reoptic
5.b. enzymatic degradation
5.c. diffusion away from the gap

Question 8

Sympathetic Nervous System

Answer 8

• Responsible for ‘fight or flight’ response
• Has a shorter preganglion but has postganglion
• Prepares the body to deal with exciting and stressful situations
• Main Terminal Neurotransmitter: Norepinephrine
• Receptor Organ Cells: Alpha 1, Alpha, 2, Beta 1, Beta 2

Question 9

Parasympathetic Nervous System

Answer 9

• Responsible for ‘rest and digest’ response
• Has a longer preganglion and the postganglion is near the effector organs
• Acts as a peace maker allowing restoration processes to occur quietly and peacefully.
• Main Terminal Neurotransmitter: Acetylcholine
• Receptor Organ Cells: nicotinic, muscarinic

Question 10

Acetylcholinesterase

Answer 10

An enzyme that inactivates acetylcholine before reaching the organ cells.

Question 11

Receptor Theory

Answer 11

Drugs act through receptors by binding to the receptors to initiate or prevent a response.

Question 12

Agonist and Antagonist

Answer 12

Agonist is drugs that block a response while Antagonist are the drugs that produce a response.

Question 13

Four Kinds of Autonomic Nervous System Drugs

Answer 13

1. Adrenergic Agonist - An autonomic nervous system drugs that stimulate the SNS and a sympathomimetic or mimics the effects of the norepinephrine.
2. Adrenergic Antagonist - An autonomic nervous system drugs that inhibit the SNS and sympatholytic or blocks the effect of the SNS.
3. Cholinergic Agonist - An autonomic nervous system drugs that stimulate the PNS and para-sympathomimetic. Adverse Reactions are DUMBBELS (diarrhea, urination, miosis and muscle weakness, bronchorrhea, bradycardia, emesis, lacrimation, salivation/sweating)
4. Cholinergic Antagonist - An autonomic nervous system drugs that inhibit the PNS and para-sympatholytic.

Question 14

Pharmacologic Effect of Autonomic Drugs

Answer 14

When autonomic drugs are given, the goal is not to treat an autonomic disorder, it is to correct the disorder of target organs through autonomic nerves.

Question 15

Category Based on Mechanisms of Action

Answer 15

1. Direct Acting Sympathomimetic - directly affects the receptor organs
2. Indirect - Acting Sympathomimetic - act by providing more norepinephrine to act on the receptors.
3. Mixed - Acting Sympathomimetic - acts by both mechanism.

Question 16

Category Based on Chemical Structure

Answer 16

1. Catecholamines - has a catechol ring and amines
2. Noncatecholamines - has no catechol ring

Question 17

Selective vs. Non-Selective

Answer 17

Selective - influences one type of the receptor
Non - Selective - influences all receptors

Question 18

Adrenergic Blockers

Answer 18

Blocks alpha and beta receptor blockers by directly and indirectly.
Direct blocking is when it occupies the receptors and indirect blocking is when it inhibits the release of neurotransmitters.

Question 19

Alpha Blockers and Beta Blockers

Answer 19

Alpha blockers causes relaxaion of smooth muscles, vasodilation, and reduces contraction of smooth muscle in bladder and prostate. And it usually ends with ‘zosin’ such as terazosin, doxazosin, and prazosin.

Beta blockers decreases heart rate, blood pressure, useful for treating mild to moderate hypertension, angina pectoris and myocardial infarction, and usually ends with ‘olol’ such as atenolol, propanolol, pindolol, timolol, metoprolol.

Question 20

Orthostatic Hypotension

Answer 20

A decrease of 20 mm Hg or more in SBP, a decrease of 10 mm Hg or more in DBP and/or an increase in the HR of 20 beats per minute or more from supine to standing - Lewis

Question 21

CHOLINERGIC CRISIS

Answer 21

Caused by overdose of cholinergic agonists

Question 22

Ganglionic Blockers

Answer 22

Nicotine
- stimulate and blocks cholinergic function and increase production of neurotransmitters.

Question 23

Depolarizing Agents

Answer 23

Succinylcholine
- causes sodium channels to open for prolonged depolarization