Central Nervous Central Nervous System StimulantsSystem Stimulants

Constricted Blood VesselsConstricted Blood Vessels Increased PulseIncreased Pulse Increased Blood PressureIncreased Blood Pressure Increased Energy, alertness, and Increased Energy, alertness, and

strengthstrength EuphoriaEuphoria Decreased appetiteDecreased appetite

Drug Effects on Drug Effects on Neurotransmission: Neurotransmission:

NicotineNicotine Acts on cell body in VTA to Acts on cell body in VTA to

increase number of action increase number of action potentialspotentials

Also binds to receptors on axon Also binds to receptors on axon terminals in nucleus accumbens terminals in nucleus accumbens to release more dopamine with to release more dopamine with each action potentialeach action potential

Nicotine’s Impact on Nicotine’s Impact on Nerve CellsNerve Cells

Nicotine binds to Nicotine binds to presynaptic presynaptic neuron receptorsneuron receptors

Causing neuron Causing neuron to excite-firing to excite-firing more action more action potentialspotentials

More dopamine More dopamine is releasedis released

Drug Drug EffectsEffects on the on the

CellCell Drugs of abuse all directly or indirectly Drugs of abuse all directly or indirectly

increase dopamine binding to post synaptic increase dopamine binding to post synaptic receptor with acute behavioral effectsreceptor with acute behavioral effects

Chronically, this increases cAMP levels and Chronically, this increases cAMP levels and leads to a cascade of changed cell activityleads to a cascade of changed cell activity

Drug Effects on Drug Effects on Neurotransmission: Neurotransmission:

CaffeineCaffeineMild StimulantMild StimulantPrevents another chemical Prevents another chemical

(adenosine) from binding (adenosine) from binding to its receptor (antagonist)to its receptor (antagonist)–Adenosine is a natural Adenosine is a natural sleep inducersleep inducer

Drug Effects on Drug Effects on Neurotransmission: Neurotransmission: CocaineCocaine

Blocks the Blocks the dopamine dopamine transportertransporter

Rapid rise of Rapid rise of dopamine in dopamine in synapsesynapse– Binds post Binds post

synaptic receptorssynaptic receptors– Initial EuphoriaInitial Euphoria

Cocaine’s Impact on Cocaine’s Impact on Nerve CellsNerve Cells

Cocaine blocks Cocaine blocks dopamine dopamine transportertransporter

Inhibits Inhibits reuptake of reuptake of dopaminedopamine

Prolonging the Prolonging the stimulationstimulation

Other Chronic Drug Other Chronic Drug EffectsEffects

Cell DeathCell Death– Neurons Neurons

don’t grow don’t grow backback

Alcohol, Alcohol, ecstasy, ecstasy, methmeth

Effect Effect memory, memory, mood, mood, learninglearning

Your Brain on DrugsYour Brain on Drugs

1-2 Min 3-4 5-6

6-7 7-8 8-9

9-10 10-20 20-30

Your Brain After Drugs

Nature VideoNature Video Cocaine VideoCocaine Video

Front of BrainFront of Brain

Back of BrainBack of Brain

AmygdalaAmygdalanot lit upnot lit up

AmygdalaAmygdalaactivatedactivated

Persistent Effects of Drug UsePersistent Effects of Drug Use

Cues for Cocaine and Cues for Cocaine and Normal Pleasures Normal Pleasures Activate Brain Sites Activate Brain Sites Childress, 1999Childress, 1999

Cues for CocaineCues for Cocaine– Cocaine abusers may experience a Cocaine abusers may experience a

powerful urge to use when they powerful urge to use when they encounter environmental cues encounter environmental cues associated with useassociated with use

– Limbic regions of the brain are Limbic regions of the brain are activated when watching cocaine- activated when watching cocaine- related videosrelated videos

Childress, 1999Childress, 1999

Persistent Effects of Persistent Effects of DrugDrug

As a result of intracellular changes, the As a result of intracellular changes, the previously cocaine addicted brain has previously cocaine addicted brain has persistently altered functioning persistently altered functioning (craving)(craving)

Environmental CuesEnvironmental Cues