Question by pingping: how does cocaine effects the different parts of the brain?
what is dopamine? how does cocaine effects the different parts of the brain?

Best answer:

Answer by amie r
The most extensively studied effect of cocaine on the central nervous system is the blockage of the dopamine transporter protein. Dopamine transmitter released during neural signaling is normally recycled via the transporter; i.e., the transporter binds the transmitter and pumps it out of the synaptic cleft back into the pre-synaptic neuron, where it is taken up into storage vesicles. Cocaine binds tightly at the dopamine transporter forming a complex that blocks the transporter’s function. The dopamine transporter can no longer perform its reuptake function, and thus dopamine accumulates in the extracellular space (synaptic cleft). This results in an enhanced and prolonged post-synaptic effect of dopaminergic signalling at dopamine receptors on the receiving neuron. Prolonged exposure to cocaine, as occurs with habitual use, leads to homeostatic dysregulation of normal (i.e. without cocaine) dopaminergic signaling via downregulation of dopamine receptors and enhanced signal transduction. The decreased dopaminergic signalling after chronic cocaine use may contribute to depressive mood disorders and sensitize this important brain reward circuit to the reinforcing effects of cocaine (e.g. enhanced dopaminergic signalling only when cocaine is self-administered). This sensitization contributes to the intractable nature of addiction and relapse.

Dopamine-rich brain regions such as the ventral tegmental area, nucleus accumbens, and prefrontal cortex are frequent targets of cocaine addiction research. Of particular interest is the pathway consisting of dopaminergic neurons originating in the ventral tegmental area that terminate in the nucleus accumbens. This projection may function as a “reward center”, in that it seems to show activation is response to drugs of abuse like cocaine in addition to natural rewards like food or sex. While the precise role of dopamine in the subjective experience of reward is highly controversial among neuroscientists, the release of dopamine in the nucleus accumbens is widely considered to be at least partially responsible for cocaine’s rewarding effects. This hypothesis is largely based on laboratory data involving rats that are trained to self-administer cocaine. If dopamine antagonists are infused directly into the nucleus accumbens, well-trained rats self-administering cocaine will undergo extinction (i.e. initially increase responding only to stop completely) thereby indicating that cocaine is no longer reinforcing (i.e. rewarding) the drug-seeking behavior.

Cocaine also blocks sodium channels, thereby interfering with the propagation of action potentials; thus, like lignocaine and novocaine, it acts as a local anesthetic. Cocaine also causes vasoconstriction, thus reducing bleeding during minor surgical procedures. The locomotor enhancing properties of cocaine may be attributable to its enhancement of dopaminergic transmission from the substantia nigra. Recent research points to an important role of circadian mechanisms and clock genes in behavioral actions of cocaine.

Because nicotine increases the levels of dopamine in the brain, many cocaine users find that consumption of tobacco products during cocaine use enhances the euphoria. This, however, may have undesirable consequences, such as uncontrollable chain smoking during cocaine use (even users who do not normally smoke cigarettes have been known to chain smoke when using cocaine), in addition to the detrimental health effects and the additional strain on the cardiovascular system caused by tobacco.

In addition to irritability, mood disturbances, restlessness, paranoia, and auditory hallucinations, crack can cause several dangerous physical conditions. It can lead to disturbances in heart rhythm and heart attacks, as well as chest pains or even respiratory failure. In addition, strokes, seizures and headaches are common in heavy users.

Cocaine can often cause reduced food intake, many chronic users lose their appetite and can experience severe malnourishment and significant weight loss.

Add your own answer in the comments!

Quantitative Approaches Provide New Perspective On Development Of Antibiotic …

Filed under: drug abuse help centers

A prominent example is the rapid emergence of cancer lines resistant to drug treatment, which underlies most failures in cancer drug therapies. While there are obviously numerous differences between the evolution of drug resistance in bacteria and in …
Read more on RedOrbit

Paterson man arrested for selling drugs at substance abuse treatment center

Filed under: drug abuse help centers

PATERSON — Police arrested a 55-year-old man outside a drug-treatment center and charged him with distributing prescription medication inside the facility, according to a report on NorthJersey.com. Luis Pou was busted at the Straight & Narrow complex, …
Read more on The Star-Ledger – NJ.com

Robbie Williams still gets high, will buy Teddy drugs

Filed under: drug abuse help centers

The confession itself might not be so shocking, if the singer and father of 14-month-old daughter Theodora hadn't previously battled both addiction to drugs and alcoholism. “Since the birth of Theo I've become less reckless,” Robbie Williams, whose …
Read more on BabyCenter (blog)