Biopsychology Chapter 15 (Drugs)

Front 1

Drug Administration and Absorption
Drugs are usually consumed in the following ways: ???

Back 1

* Ingestion - Or oral administration--can be absorbed from the digestive tract; most drugs are absorbed from the small intestine, but some (e.g., alcohol) can be absorbed through the stomach wall, and thus act more rapidly
* Injection - Wether SC, IM, or IV, is the favored route in medical practice because effects of injected drugs are STRONG, FAST, and PREDICTABLE; in particular, addicts favor the IV route.
* Inhalation - Allows many chemicals to be absorbed directly into the blood stream from the lungs (e.g., chemicals in tobacco and marijuana smoke); absorption through mucous membranes allows some drugs (e.g., cocaine) to be redly absorbed through the mucous membranes of the nose, mouth, or rectum.

Front 2

Drug penetration of the CNS
The _____ makes it difficult for may drugs to enter the CNS.

Back 2

Blood-Brain Barrier

Front 3

Mechanisms of Drug Addiction
Once a psychoactive drug has penetrated the CNS, it can influence neural activity in numerous ways; e.g., it can act diffusely on _____ or interact specifically with particular classes of _____ and _____.

Back 3

Neural Membranes
Neurotransmitters and Receptors

Front 4

Drug Metabolism and Elimination
The effects of most psychoactive drugs are terminated by their _____.

Back 4

Metabolism

Front 5

Drug Tolerance
Drug tolerance is a state of decreased sensitivity to a drug's effect that results from prior exposure to the drug.
Tolerance can be measured in two ways: ?????

Back 5

1) By measuring the DECREASE IN THE RESPONSE elicited by the same dose of the drug
2) By measuring the INCREASE IN THE AMOUNT OF DRUG required to produce the same effect. Exposure to one drug can lead to the development of tolerance to another drug's effects (CROSS TOLERANCE).

Front 6

Drug Withdrawal and Effects and Physical Dependence
After significant amounts of a drug have been in the body for a period of time, its sudden elimination can trigger an illness called a _____; these are usually opposite to the initial effects of the drug. When someone suffers from withdrawal symptoms if they stop taking a drug, they are said to be _____ on the drug.

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Drug Withdrawal Syndrome
Physically Dependent

NOTE: Addiction does not equal physical dependence

Front 7

Role of Learning in Drug Tolerance, and Withdrawal
There are 3; what are they?

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1) Contingent Drug Tolerance - Is tolerance that develops only to dug effects that are actually experienced
2) Conditioned Drug Tolerance - Refers to tolerance that is maximally expressed in the presence of drug-predictive stimuli (for example Crowell, Hinson, and Siegel (1981) demonstrated conditioned tolerance to the hypothermic effect of alcohol. One theory of the situational specificity of tolerance is Siegel's conditioned compensatory response theory.)
3) Conditioned Withdrawal Effects - These withdrawal effects that are elicited by the drug environment or tother drug-associated cues; conditioned response to drug-predictive cues in the absence of the drug itself.

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Five commonly Abused Drugs
What are they???

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Nicotine
Alcohol
Marijuana
Cocaine and Other Stimulants
Opiates (Heroin and Morphine)

Front 9

Marijuana elicts _____ responses largely due to _____ (delta-9-tetrahydrocannabinol). It may be _____ or ingested _____ (baked into an oil-rich substrate to aid absorbtion). Marijuana elicits its CNS effects at _____ receptors in teh brain; these are especially common in the _____, _____, and _____.
These receptors are believed to bind the endogenous THC-like chemical called _____, an endogenous ligand that may play a neuroprotective role in the brain.

Back 9

Psychoactive responses
THC
Inhaled or injested Orally
Cannabinoid receptors
Basal Ganglia, Cerebellum, and Hippocampus
Anadamide

Front 10

Cocaine and Other Stimulants
Cocaine is the most commonly abused stimulant; it may be inhaled, absorbed across mucosal membranes, or injected. Cocaine is very addictive; however, its withdrawal syndrome is relatively mild.
Cocaine acts by blocking _____; its euphoria-inducing properities seem to be due to its effects on depaminergic neurotransmission.

Back 10

Catecholamine Reuptake

Front 11

Cocaine and Other Stimulants
Amphetamine and related compounds like _____ are also commonly abused stimulants; currently favored amphetamine-like drugs of abuse include _______ and _____.

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Methamphetamine
Methamphetamine and Ectasy

Front 12

The Opiates: Herion and Morphine
This family of drugs includes _____, _____, and ______.
These are unmatched as _____ and are very addictive.
Opiates elicit their effects on the CNS by acting as receptors in the brain that normally bind _____ (also called _____).
The increase in heroin is almost entirely due to legal synthetic opiod analgesics (such as ______ and ______). _____ has been approved for use as a treatmetn for addicts.

Back 12

Morphine, Codine, and Heroin
Analgestics
Endogenous Opiates also called Endorphins
Oxycontin and Lorcet
Buprenorphine

Front 13

Biopsychology Theories of Addiction
What are they???

Back 13

1) PHYSICAL-DEPENDENCE and POSITIVE-INCENTIVE PERSPECTIVES OF ADDICTION
* Early attempts to explain addiction attributed it to physical dependence; addicts take drugs to curtail the withdrawal symptoms that they otherwise would face.
* The failings of physical-dependence theories have lent support to positive-incentive theories; according to positive-incentive theories of addiction, most addicts take dugs to obtain their pleasurable effects, rather than to escape their aversive aftereffects.
2) FROM PLEASURE TO COMPULSION: INCENTIVE-SENSITIZATION THEORY:
* Robinson and Berridge (2003) expectation of the pleasurable effects of drugs may become sensitized in addicts; a key point of this incentive-sensitization theory is that addicts don't receive more pleasure from the drug; anticipated pleasure motivates their behavior.
3) RELAPSE and ITS CAUSES:
* Most addicts relapse at some point after they stop taking drugs. Three different causes have been identified: STRESS, DRUG PRIMING, and CONDITIONED ENVIRONMENTAL CUES.

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INTRACRANIAL SELF-STIMULATION (ICSS) and the PLEASURE CENTER of the BRAIN
Although animals self-stimulate a variety of brain structures, most studies focused on the _____ and ______ because the self-stimulation rates at these sites are impressively high.

Back 14

Septum and Lateral Hypothalamus

Front 15

INTRACRANIAL SELF-STIMULATION (ICSS) and the PLEASURE CENTER of the BRAIN
-Mesotlencephalic Dopamine System and Intracranial Self-Stimulation-
The mesotelecephalic dopamine system ascends from two mesencphalic dopaminergic nuclei: the _____ and the _____.
Most of the axons of substantia neurons terminate in the striatum and are commonly referred to as the _____; these neurons degenerate in patients with Parkinson's disease.
The axons of ventral tegmental area neurons project to the limbic system and cortex (in particular the nucleus accumbens) and are commonly referred to as the mesocortical limbic pathway; this pathway appears to be most important to the rewarding effects of natural reinforcers, brain stimulation, and drugs.

Back 15

Substantia Nigran and the Ventral Tegmental Area
Nigrostriatal Pathway

Front 16

Early Studies of Brain Mechanisms of Addictions: Dopamine
The Nucleus Accumbens and Drug Addiction
Using ICSS, self-administration, and place-preference conditioning paradigms, investigators have established four major lines of evidence support the view that the mesotelencephalic dopamine system, particularly mesocorticolimbic terminals in the _____, mediates the rewarding effects of drugs, as well as the effects of natural reinforcers:
* Laboratory animals self-administer microinjections of addictive drugs into the nucleus accumbens
* Microinjections of drugs into the nucleus accumbens lead to the development of Conditioned Place-Perefences
* Destruction of the VTA or the nucleus accumbens has been shown to block self-administration of the development of conditioned place preferences;
* Self-administration of addictive drugs or natural reinforcers are both associated with increased dopamine release in the nucleus accumbens.

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Nucleus Accumbens