Chapter 12: Basic Principles of Neuropharmacology

Question 1

Neuropharmacology

Answer 1

The study of drugs that alter processes controlled by the nervous system.

Question 2

Neuropharmacologic agents

Answer 2

1) peripheral nervous system (PNS) drugs

2) central nervous system (CNS) drugs.

Question 3

Axonal Conduction

Answer 3

Drugs that act by altering axonal conduction are not very selective. It will affect conduction in all nerves to which it has access. It is not selective and cannot reverse the process of impulse transmission. Local anesthetics are examples of these drugs.

Question 4

Synaptic Transmission

Answer 4

Drugs that alter synaptic transmission can produce effects that are highly selective.
The effects of drugs on synaptic transmission and the impact on binding to receptors include direct receptor activation, enhanced response to T, and blockage of T binding.
Reduced storage of T occurs with the step called storage of transmitter, and inhibition of T breakdown occurs with the step called termination of transmission.

Question 5

Receptors

Answer 5

The impact of a drug on a neuronally regulated process is dependent on the ability of that drug to directly or indirectly influence receptor activity on target cells.

Question 6

Steps in Synaptic Transmission

Answer 6

Step 1: Transmitter Synthesis.
Step 2: Transmitter Storage.
Step 3: Transmitter Release.
Step 4: Receptor Binding.
Step 5: Termination of Transmission.

Question 7

*****You need three types of information to predict the major effects of any PNS drug.

Answer 7

1) Type of receptor through which the drug acts
2) Normal response to activation of those receptors
3) What the drug in question does to receptor function

Question 8

Step 1: Transmitter Synthesis.

Answer 8

Requires molecules to be present in the nerve terminals

Question 9

Step 2: Transmitter Storage.

Answer 9

Takes place within vesicles. Once transmitter is synthesized, it must be stored until the time of its release.

Question 10

Step 3: Transmitter Release.

Answer 10

Initiates a process in which vesicles undergo fusion. Release of transmitter is triggered by the arrival of an action potential at the axon terminal.

Question 11

Step 4: Receptor Binding.

Answer 11

Diffuse across the synaptic gap and then undergo reversible binding to receptors on the postsynaptic cell.

Question 12

Step 5: Termination of Transmission.

Answer 12

Alllows the transmitter to be removed from the synaptic gap by the processes of reuptake, enzymatic degradation, and diffusion.
1) block transmitter reuptake
2) inhibition of transmitter degradation
Drugs that act by either mechanism will increase transmitter availability, thereby causing receptor activation to increase.

Question 13

Isoproterenol

Answer 13

Can elicit three major responses:

1) increased cardiac output (by increasing heart rate and force of contraction)
2) dilation of the bronchi
3) elevation of blood glucose. Bronchial dilation allows more air to enter the lungs, thus decreasing respiratory rate.

Question 14

Drugs that act directly at receptors

Answer 14

morphine
epinephrine
insulin

Question 15

Drugs that bind to receptors and prevent their activation

Answer 15

naloxone
antihistamines
propranolol

Question 16

Drugs that bind to receptors and thereby enhance the actions of a natural transmitter

Answer 16

benzodiazepines

Question 17

Beta 1 receptors

Answer 17

Increased heart rate and increased force of cardiac contractions.

Question 18

Beta 2 receptors

Answer 18

Bronchial dilation and elevation of blood glucose levels.

Question 19

Botulinum toxin

Answer 19

Blocks the release of acetylcholine by the neuron that controls skeletal muscles, which paralyzes the respiratory muscles causing respiratory failure.