Cocaine

Cocaine (from French 'cocaïne', from Spanish, 'coca', ultimately from Quechua 'kúka'.) is a tropane alkaloid and stimulant drug obtained primarily from the leaves of two coca species, Erythroxylum coca and Erythroxylum novogranatense. It is most commonly used as a recreational drug and euphoriant. After extraction from coca leaves, cocaine may be snorted, heated until sublimated and then inhaled, or dissolved and injected into a vein. Mental effects may include an intense feeling of happiness, sexual arousal, loss of contact with reality, or agitation. Physical symptoms may include a fast heart rate, sweating, and dilated pupils. High doses can result in high blood pressure or body temperature. Effects begin within seconds to minutes of use and last between five and ninety minutes.Cocaine crosses the blood-brain barrier via a proton-coupled organic cation antiporter and (to a much lesser extent) via passive diffusion. Cocaine acts as an indirect sympathomimetic by blocking the dopamine transporter, inhibiting reuptake of dopamine from the synaptic cleft into the pre-synaptic axon terminal; the higher dopamine levels in the synaptic cleft increase dopamine receptor activation in the post-synaptic neuron, which drives the effects of euphoria and arousal. Cocaine also blocks the serotonin transporter and norepinephrine transporter, inhibiting reuptake of serotonin and norepinephrine from the synaptic cleft into the pre-synaptic axon terminal and increasing activation of serotonin receptors and norepinephrine receptors in the post-synaptic neuron, contributing to the modulation of consciousness, emotions, and movements that characterize cocaine exposure.Cocaine is addictive due to its effect on the reward pathway in the brain. A single dose of cocaine induces tolerance to the drug's effects.