. Cocaine disturbs dopamine transporters, causing increased extracellular dopami
ID: 278032 • Letter: #
Question
. Cocaine disturbs dopamine transporters, causing increased extracellular dopamine levels that remain for longer periods of time in the nucleus accumbens. After chronic use, many individuals begin to develop tolerance to dopamine release through receptor modifications. 8 pts
What specific type of receptors do you think will be impacted by this change? Where are these receptors located? 2 pts
Will the number of available receptors increase or decrease or stay the same? Explain why. 2 pts
Explain how the effect described in your previous answer will affect the response of the nucleus accumbens neurons to DA release 1) when taking cocaine and 2) after the individual stops taking cocaine. 4 pts
Explanation / Answer
1). Cocaine is a monoamine reuptake inhibitor. This results in CNS excitation and addiction (due to reward pathway stimulation). It acts by reducing the dopamine uptake and increases the dopamine levels, which causes CNS excitation. With continuous increased intake of cocaine, tolerance develop by means of reduced receptor number and functional desensitization of the receptors. This occurs because the body tries to reduce the excessive dopamine activity by reducing the receptor number and by desensitizing the receptors. Especially, the functional desensitization of D1 receptors and reduced number of D2 receptors were observed in the research studies. So, the person have to take more cocaine to produce the effect of CNS excitation, which leads to cocaine addiction.
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