Drugs and Society Chapter 4 Part 2

spinal cord

This transmits information from sensory nerves to the brain and carries motor commands from the brain to the muscles.

medulla oblongata

The area at the base of the brain, where the spinal cord arises, is called the _____. It is made up, in part, of fiber tracts running to and from the spinal cord and connecting to higher centers in the brain, such as the motor cortex. The proper functioning of the autonomic nervous system depends on the general level of arousal in this

The pons

This is a large bulbous structure located in the hindbrain, above the medulla. It too contains nuclei of the reticular formation that play a role in sleep and arousal. This also bridges and refines motor commands conveyed between parts of the cortex

locus coeruleus

Activity of this is modulated by input from the inhibitory neurotransmitter GABA whose neurons form synapses there.

Ionotropic and metabotropic

There are two types of receptors:

Iontropic

This receptor is fast and direct

Metabotropic

This receptor is slow and indirect

VTA

This is a vital component of the brain’s reward circuit, for both natural and drug reinforcers. It is the site of origin for the projection pathway called the medial forebrain bundle.

VTA

This contains cell bodies of dopamine-producing neurons that project to and release dopamine in multiple regions of the brain, including the thalamus; hypothalamus; substantia nigra; nucleus accumbens; areas of the limbic system including the hippocampus, septal nuclei, and amygdala; and the prefrontal cortex

VTA

this contains neurons that produce GABA and glutamate

basal ganglia

These are located just under the cortex and are important in controlling voluntary movement, action selection and switching between motor behaviors, motor habits, and eye movement. In addition to motor actions, this control some cognitive processes such as memory for locations in space and classical conditioning of behaviors.

Agonist

This binds to a receptor and activates it

Inverse Agonist

A drug might bind to a receptor site but, instead of mimicking the neurotransmitter’s action or entirely blocking its effect, the drug produces an effect opposite that of the neurotransmitter.

An antagonist

This blocks the action of the agonist and does NOT produce an opposite effect

Amino Acid Neurotransmitters

This is the simplest type of neurotransmitter

Amino Acid Neurotransmitters

The most widely distributed NT in brain

Amino Acid neurotransmitters

Can be either excitatory or inhibitory

Excitatory NTs

These make it MORE likely that the neuron will “fire” or cause an AP

Inhibitory NTs

These make it LESS likely that the neuron will “fire” or cause an AP

Amino Acid neurotransmitters

Examples include Glutamate, aspartate, glycine, GABA

Glutamate

This is the most abundant excitatory NT in brain and plays an important role in neural plasticity, cognition, learning and memory as well as motor functions

GABA

The primary inhibitory NT in the brain

Acetylcholine (Ach)

In the brain, works to increase plasticity (memory)

Acetylcholine (Ach)

In the body works on the parasympathetic nervous system

Acetylcholine (Ach)

This is an excitatory NT that is involved at neuromuscular junctions

antagonists

Many neurotoxins (released by bacteria) are_____ at the Ach receptor

Monoamine Neurotransmitters

Synthesized from single amino acid

catecholamines and indolamines

What are the two types of monoamine neurotransmitters

Dopamine

This is the “reward” neurotransmitter but is also involved in movement, mood, cognition

agonist

Many commonly abused drugs (cocaine, amphetamines) increase dopamine levels by acting as an

Norepinephrine (NE)

In the body, works mostly on the sympathetic nervous system

 Dilates pupils

 Increases HR

 Increases glucose in liver

Dopamine, Norepinephrine, Epinephrine

Select the catecholamines:

A. Dopamine

B. Norepinephrine

C. GABA

D. Epinephrine (E)

Norepinephrine (NE)

In the brain, this works to mobilize energy

 Focuses attention

 Increases sensory acuity

Epinephrine (E)

Similar to norepinephrine, has important role in the fight or flight response

Epinephrine (E)

Also has a role in memory enhancement during emotionally stressful times

Serotonin

Select the Indolamine Neurotransmitters

GABA

Dopamine

Epinephrine

Serotonin

Serotonin

Commonly known as the “happy” chemical in the brain but it has many functions

Serotonin

Important role in mood control

Basal Ganglia

Involved in initiating and controlling movement

to the cortical areas (mesocortical pathway) and to the Nucleus Accumbens (mesolimbic pathway)

Ventral Tegmental Area (VTA) has two projections:

T

T/F Ventral tegmental area (VTA) —> Nucleus Accumbens (NAcc)

Amygdala

Almond shaped nuclei located in medial temporal lobe

• Center for “emotional memory”

Hippocampus

Involvement in spatial memory

PAG

Electrical stimulation of this leads to increased defensive behavior and triggers fight/flight response

• has a role in analgesic response via release of enkephalins

PAG

primary area involved in pain reduction

Heroin, morphine, hydrocodone, oxycodone

Which of the following Drugs affect the PAG:

heroin

morphine

hydrocodone

oxycodone

THC

Endorphins

These are the body’s natural morphine is release from hypothalamus and pituitary

Prefrontal Cortex

Involved in decision making, emotions, memory

and attention

• One of the last areas of the brain to fully develop

Medulla

Which structure is this describing:

Barbiturates, opioids, and alcohol depress this

Contains the vomiting center and the respiration center

T

T/F Most drugs have some effect on the hippocampus