Leslie participated in a research study in which she was given a dose of Ritalin and reported to researchers that she found the
effects pleasurable. Other participants given the same dose reported the effects were unpleasant. What did researchers find when they compared dopamine receptors in her brain to those who found the drug unpleasant? A. Leslie had fewer dopamine receptors than other participants.
B. Leslie had more dopamine receptors than other participants.
C. There was no difference in the numbers of dopamine receptors.
D. Only Leslie had dopamine receptors.
B. Leslie had more dopamine receptors than other participants.
Explanation:
Ritalin (methylphenidate hydrochloride) is a central nervous system stimulant drug used to treat Attention Deficit Hyperactivity Disorder (ADHD). Ritalin also serves to treat narcolepsy, a sleep disorder that is characterized by excessive daytime sleepiness, even if the person has slept well at night.
Ritalin increases the activity of certain areas of the brain that are poorly active, promoting increased attention and concentration, and decreasing impulsive behavior. In narcolepsy, Ritalin works by relieving sleep throughout the day. The mechanism of action of Ritalin is the same as that of amphetamines and other stimulants, ie it increases the concentration and reuse of neurotransmitters such as dopamine and norepinephrine in the brain. For this reason, people with more dopamine receptors in their brain (such as Leslie) when taking ritalin feel pleasant feelings.
Since carbon dioxide is needed in the photosynthesis process, then much of the carbon dioxide which is produced by green plants is not always excreted in form of metabolic waste because it can be easily used in the photosynthesis process.
