Biological Mechanisms of Addiction
The pursuit of pleasure lures some individuals onto an hedonic treadmill that paradoxically makes them miserable, and from which they cannot escape. Below are some of the biological mechanisms:1. Depressant Effects of AlcoholAlcohol reduces the pace of brain activity by decreasing the excitatory action of the neurotransmitter glutamate and increasing the inhibitory actions of the neurotransmitter GABA. This temporary decrease in brain performance is responsible for the What Makes Intoxication Rewarding 2. Down & Up Regulation
3. Acute Alcohol Withdrawal Syndrome
3. Neuroadaptation and Voluntary BehaviorRepeated exposure to a drug produces long term changes in nervous system.
The transition from voluntary use to addiction occurs through a combination of processes, including neuroadaptations that result from repeated exposure to the addictive experience. Sensitization is behind the compulsion to engage in the addictive behavior.4 An individual makes a voluntary decision to experiment with the addictive experience. But continued exposure to this experience over time produces neuroadaptations that show up as a compulsive attraction to the addictive experience. If the term disease is appropriate for addictive disorders, it refers to the changes in brain structure and function that give rise to dependence and self-destructive behavior patterns we see in addictive disorders. 4. Withdrawal: Acute and Chronic EffectsWell understood biological reactions underlie both the short-term [acute] response to drug ingestion, and the establishment of the long-term [chronic] craving that characterizes addiction. Of concern is the recent discovery that some neuroadaptations are irreversible! Once the body has been altered by repeated drug administrations, the absence of the drug produces a persistent discomfort that seeks removal by a return to the familiar comfort that would result from a return to the addictive behavior. 5. Addiction and Volition (Will)Most people who have fallen into an addictive trap never escape. However, good long-term outcome is possible, and high-functioning individuals who appreciate the true nature of their challenge and have access to effective relapse prevention strategies can enhance the power of their will so they are able to act in accord with their interests and principles. References: 1. Gordis, E. Alcohol, the Brain, and Behavior. Alcohol Research and Health. 2000, 24, 12-15 2. Becker, H. Kindling in Alcohol Withdrawal. Alcohol Research and Health. 1998, 22, 25-33 3. Adinoff, B, etal. Disturbance of the Stress Response. Alcohol Research and Health. 1998, 22, 67-71. 4. Robinson, R & Berridge, K. The Neural Basis of Drug Craving.
Brain Research Reviews, 1993, 17, 247-291 What happens when receptors are upregulated?In biology, the process by which a cell increases its response to a substance or signal from outside the cell to carry out a specific function. For example, a cell may increase the number or activity of protein receptors or other molecules on its surface to make it more sensitive to a hormone or drug.
What is upregulation and downregulation of receptors?A mechanism for the increased or decreased sensitivity to agonists and antagonist drugs suggests that decreased exposure to an agonist results in an increase in the number of receptors (upregulation), while increased exposure to an agonist can result in a decrease in the number of receptors (downregulation).
What is up regulation and down regulation quizlet?Upregulation. An increase of a cellular component. Example of downregulation. The cellular decrease in the number of receptors to a molecule, such as a hormone or neurotransmitter, which reduces the cell's sensitivity to the molecule.
What is downregulation in pharmacology?Downregulation • Downregulation specifically refers to a reduction in the total number of receptors available to be stimulated due to prolonged receptor activation (e.g. by chronic treatment with a pharmacological agonist drug or prolonged inhibition of metabolism of a neurotransmitter).
|