Central Nervous System Stimulants Constricted Blood Vessels Constricted Blood Vessels Increased Pulse Increased Pulse Increased Blood Pressure Increased Blood Pressure Increased Energy, alertness, and strength Increased Energy, alertness, and strength Euphoria Euphoria Decreased appetite Decreased appetite

Drug Effects on Neurotransmission: Nicotine Acts on cell body in VTA to increase number of action potentials Acts on cell body in VTA to increase number of action potentials Also binds to receptors on axon terminals in nucleus accumbens to release more dopamine with each action potential Also binds to receptors on axon terminals in nucleus accumbens to release more dopamine with each action potential

Nicotine’s Impact on Nerve Cells Nicotine binds to presynaptic neuron receptors Nicotine binds to presynaptic neuron receptors Causing neuron to excite-firing more action potentials Causing neuron to excite-firing more action potentials More dopamine is released More dopamine is released

Drug Effects on the Cell Drugs of abuse all directly or indirectly increase dopamine binding to post synaptic receptor with acute behavioral effects Drugs of abuse all directly or indirectly increase dopamine binding to post synaptic receptor with acute behavioral effects Chronically, this increases cAMP levels and leads to a cascade of changed cell activity Chronically, this increases cAMP levels and leads to a cascade of changed cell activity

Drug Effects on Neurotransmission: Caffeine Mild Stimulant Mild Stimulant Prevents another chemical (adenosine) from binding to its receptor (antagonist) Prevents another chemical (adenosine) from binding to its receptor (antagonist) –Adenosine is a natural sleep inducer

Drug Effects on Neurotransmission: Cocaine Blocks the dopamine transporter Blocks the dopamine transporter Rapid rise of dopamine in synapse Rapid rise of dopamine in synapse –Binds post synaptic receptors – Initial Euphoria

Cocaine’s Impact on Nerve Cells Cocaine blocks dopamine transporter Cocaine blocks dopamine transporter Inhibits reuptake of dopamine Inhibits reuptake of dopamine Prolonging the stimulation Prolonging the stimulation

Other Chronic Drug Effects Cell Death Cell Death –Neurons don’t grow back Alcohol, ecstasy, meth Alcohol, ecstasy, meth Effect memory, mood, learning Effect memory, mood, learning

Your Brain on Drugs 1-2 Min

Your Brain After Drugs

Nature Video Cocaine Video Front of Brain Back of Brain Amygdala not lit up Amygdala activated Persistent Effects of Drug Use

Cues for Cocaine and Normal Pleasures Activate Brain Sites Childress, 1999 Cues for Cocaine Cues for Cocaine – Cocaine abusers may experience a powerful urge to use when they encounter environmental cues associated with use –Limbic regions of the brain are activated when watching cocaine- related videos Childress, 1999

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

Environmental Cues