Drugs and Behavior Exam 3

Pharmacodynamics

The study of what a drug does to the body, how drug molecules interact with their targets (usually receptors), and how those interactions create physiological, biomedical, and behavioral effects. 

what does pharmacodynamics explain

the effects a drug produces

what does everything about a drug’s action relay on ?

how it interacts with receptors in the body

what are the two main parts of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

Central Nervous System

Brain and Spinal Cord 

what is the main job of CNS 

the control center that processes and interprets information.

What two main cells are found in the CNS

Neurons and Glial Cells

Neurons

Messengers that send and receive electrical and chemical signals

Glial Cells

The support team that keeps neurons healthy, nourished, and functioning properly 

Peripheral Nervous System 

Includes motor and sensory nerves that connect the brain and spinal cord to the rest of the body.

Astrocytes Function

• Provide structural support for neurons.

• Maintain the ionic and chemical environment around neurons.

• Store nutrients to give energy to neurons when needed.

• Perform gliosis (repairing and scarring brain tissue after injury).

• Regulate blood flow in the CNS.

• Help coordinate glia-neuron communication.

Microglia Functions

• The brain’s immune cells.

• Perform phagocytosis, cleaning up dead cells, debris, and pathogens.

Oligodendroglia (in the CNS)

• Form myelin sheaths around multiple axons at once (think of insulation around wires).

• Inhibit regrowth of axons after neuron damage — this is why CNS neurons usually don’t regenerate.

Schwann Cells (in the PNS)

• Form myelin on a single axon.

• Release growth factors after neuron damage.

• Provide a pathway for axons to regrow and reconnect, which is why peripheral nerves can often heal over time.

what do glial cells play a role in

psychological and neurological conditions

Glial cell dysregulation is linked to disrupted brain communication in what disease 

Schizophrenia

• Glial-derived neurotrophic factor (GDNF) influences how patients respond to brain stimulation therapy in what disease 

Bipolar Disorder 

• Glial cell activity affects reward circuits and inflammation in the brain in what disease

addiction 

• what signaling can play a role in neurodegenerative conditions

• Endocannabinoid signaling (involving glial cells)

dendrites

receives messages from other neurons

Soma

Cell body

processes information 

Axon

sends the signal away from the cell body 

Axon Terminals

Release neurotransmitters into the synapse

Synapse 

gap between terminals 

Myelin Sheath

Insulates the axon to make signal transmission faster

Neurogenesis 

the creation of new neurons — an ability once thought to stop after childhood but now known to continue in parts of the adult brain (like the hippocampus).

neuroplasticity

brain’s ability to reorganize itself by forming new neural connections or strengthening/weakening existing ones.

What is neuroplasticity essential for ? 

Learning, memory, recovery from injury, and adaptation. 

how do drugs, stress, and experiences affect neuroplasticity  

they can increase or decrease it 

how do neurons communicate

using neurotransmitters

neurotransmitters

chemical messengers that cross synapses, or small gaps, between neurons

classical neurotransmitters

• Stored in vesicles in the axon terminal.

• Released when an action potential (electrical signal) arrives.

• Bind to receptors on the postsynaptic neuron.

• Examples: Dopamine, Norepinephrine, Serotonin, and many others (over 100 identified).

Non-Classical neurotransmitters

• Not stored in vesicles — they’re made on demand by enzymes.

• Examples include gas and endocannabinoids  

Gas Transmitters 

Nitric Oxide (NO) 

important for learning and memory, blocking NO can block learning 

Endocannabinoids

Lipid Based messengers

naturally made in the body and affected by substances like weed 

how do most non-classical neurotransmitters moves

backwards (retrograde signaling) from the postsynaptic cell to the presynaptic cell to fine-tune communication. with some exceptions like drugs acting outside the synapse. 

where do most psychoactive drugs act

on neurotransmitters at the synapse