Answer to Question 1
Answer: Brain areas affected by drug abuse are primarily the brain stem, cerebral cortex, and limbic system. Simplistically, chemical communication between these areas of the brain via neurotransmitters is the basis for mood and emotional response. Psychoactive drugs interfere with this balanced neurochemical communication system by altering the methods of how the brain functions. Some drugs mimic the effects of natural neurotransmitters, but other drugs trigger a rush of particular neurotransmitter, particularly dopamine, the brain's feel-good chemical. Specific drugs can cause the release of very high amounts of dopamine in the brain, providing a strong euphoria and a motivation to repeat the drug use.
Answer to Question 2
Answer: Occupation with thoughts and plans related of gambling; needing to gamble with increasingly higher amounts of money; feelings of restlessness or irritability when compelled to quit or curtail gambling; and use of gambling to escape negative emotions or feelings.
The greenhouse effect: heat trapping by earth's atmosphere.
Methods for Parenteral Administration of Drugs
Mechanism of Action of Antipsychotic Drugs
Mechanisms of Action of Antimicrobial Drugs
Antiretroviral Drugs Used for the Treatment of HIV/AIDS
Mechanisms of action of antimicrobial drugs