The effects of cocaine on the nervous system

I read this information from PRE-U TEXT STPM BILOLOGY, there are some of the effects of cocaine on the nervous system. It begin when drug users take in cocaine example snorting (inhaling) or smoking, cocaine enters into the synaptic cleft and binds to the transport molecules. This blocks the reuptake of dopamine by the presynaptic cell. The level of dopamine is higher than normal and remains longer in the synapse. This stimulates the pleasure pathway which gives drug users an intense feeling of euphoria and increased sense of energy. The feeling last for 5-30 minutes. The users then begin to feel irritable, restless and depressed. To overcome these symptoms, users have to repeat the usage of cocaine. With continued cocaine use, the body responds to the ‘excess’ supply in the synaptic cleft by producing less neurotransmitter dopamine and decreasing the numbers of receptors. The cocaine users then experience withdrawal symptoms. They become extremely dependent (addicted) to the drug and increase the cocaine intake to produce the euphoric effect. High doses of cocaine can cause nasal bleeding (from snorting), seizures, cardiac and respiratory arrest, as well as brain damage. Babies born to addict may suffer from developmental and neurological problems. Diseases such as hepatitis B and AIDS are spread when drug addicts share needles.