Chapter 11

• Cocaine

• Amphetamines – Amphetamine– Methamphetamine– Ephedrine– Cathinone – khat– MDMA – ecstasy

• Methylphenidate

• Caffeine

• Nicotine

Stimulants

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Map of principal coca-growing regions of South America

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Freud advocated use of cocaine – the wonder drug

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Cocaine use in US

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Coca leaves

Coca paste

Cocaine hydrochloride (HCl)

Freebasing

Crack

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Mechanisms of cocaine action

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Computerized tomographic (CT) scan of a thalamic hemorrhage in a crack cocaine smoker

Stimulants and DAImportant anatomical connection:Dopaminergic connections from midbrain (substantia nigra

and VTA) to striatum and nucleus accumbens

Effects:Nucleus accumbens

– Locomotor response – Reward system activation

Striatum

– Stereotyped behaviors

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Cocaine Abuse and Dependence• 10-15% of initial users become cocaine abusers• Cocaine abusers report initially using legal/illegal

drugs at about age 13-14• Initial use usually thru snorting• Factors important to changes in use patterns

– Reinforcing effects (stimulating, euphoric, confidence-boosting effects)

– Switch from snorting to smoking or IV injection

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Tolerance after chronic cocaine use

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Sensitization after chronic cocaine use

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Hypothetical relationship between cocaine use, synaptic DA levels, and mood

Withdrawal• Few withdrawal symptoms other than depression

– Acute withdrawal

Death by cocaine:• About 25% of deaths reported with cocaine use are due

to the drug effects. • Causes include:

- cerebral hemorrhaging- lethal cardiac arrhythmia- myocardial infarction (heart attack) even in individuals with no prior heart problems

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Brain Abnormalities in Cocaine Abusers• Low blood flow in some regions• Deficits in glucose utilization in frontal lobe• Decreased grey matter concentration

Consequences?Deficits in:• Verbal memory• Attention • Motor function

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