Drugs Interfere with Neurotransmission in the Brain

The organ of behavior, also the organ of the mind. People can see an individual’s overt behaviors, whereas consciousness is In our individual minds. Neuroscience studies how people control their behaviors, thoughts, and emotions. The brain regulates everything a human does.

Each is responsible for some activities necessary for life. A localization of function; “a division of labor”. Larger jobs are parceled out throughout the brain. eg, driving and texting while your body maintains HR, BP, breathing, temp.

Cerebral cortex

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“Pleasure circuit” - region of the brain that regulates pleasure related to our survival, i.e. such as sex & eating = reward.

VTA contains nerve cells devoted to producing “pleasure”. The VTA relays Their message via axons to the Nucleus Accumbens & Frontal Cortex.

(VTA)

Drugs of abuse activate the VTA by altering the release of dopamine!

A very primitive region

I. Drugs of abuse alter the communication between neurons that are mediated by dopamine in the VTA:

A. Ways of affecting synaptic transmission •  ↑ action potentials; ↑ amount of NT released •  ↑ the amount of dopamine released. •  By blocking receptors on post-synaptic neuron. •  By mimicking naturally occurring NT’s in the brain. •  By blocking re-uptake pumps “transporters”; thus

dopamine remains in the synaptic junction. •  Prevents enzymes from deactivating the NT in the

synaptic cleft.

Time

Dopamine

Levels

Cocaine (1st time use)

orgasm

Levels of dopamine in the “pleasure circuit” of the brain

1

2

meth

Cocaine and Meth block uptake pumps

meth

cocaine

amphetamine

- increases the electrical activity of dopamine releasing neurons in the brain.

A stimulant

1

Morphine, Heroin and Oxycontin- Opiates that mimic NT’s

All have pain relieving effects, but highly addictive!

All highly addictive chemicals because they increase dopamine activity in the reward pathway!

cannabinoids

THC- mimics cannabinoid NT’s

cannabinoid

receptors

THC

cannabinoid

Cannabinoid NT’s

serotonin serotonin

receptors

LSD

serotonin

Ecstacy interferes with enzyme action. Serotonin remains in the synapse longer.

Ethyl alcohol   Release of Dopamine

Cocaine blocks uptake pumps on dopamine releasing neurons

Arterial Vessels and

Venous Vessels make up the whole

vascular system

How do Drugs Get Into the Body? BRAIN

Inhaled: atrial blood (artery) in the lungs atrial chamber to heart pumped to all body parts, esp the brain.

Injected: venous blood (vein) in the arm venous chamber to heart pumped to lungs (blood becomes oxygenated) lungs atrial chamber to heart all body parts, esp the brain.

Absorbed: A longer pathway for absorption. heart pumped to all body parts, esp the brain.

Injested: Drug goes through digestive system and must pass through walls of the stomach and intestine. heart pumped to all body parts, esp the brain.

How do Drugs Get Into the Body?

BRAIN