Heroin in Powder and Pill Forms with Balloons

What are opiates?
    The most abused form of opiates is heroin.  Heroin is processed from morphine.  Heroin is typically sold as a white or brownish powder or as the black sticky substance known as "Black Tar Heroin."  Other opiates include opium, codeine, morphine, hydromorphone (Dilaudid), methadone, and meperidine (Demerol).  Opiate-like drugs behave like inhibitory neurotransmitters, as their effects are similar to the effects of GABA.  Opiates are part of the agonist family of drugs.  An agonist is a chemical that binds to a specific receptor and produces either excitation or inhibition of action potentials.  This family also includes cannabis, nicotine, and hallucinogens such as LSD.

Statistics of Heroin Use in the United States

How is heroin used? How do opiates exert their effect on the brain?
    In the early 1970's, it was demonstrated that the brain contained opiate receptors.  These receptors not only recognize opiates, but also endogenous opioids, such as endorphins, enkephalins, and dynorphins.  It must be made clear that these receptors were not designed specifically to recognize the plant alkaloid, it just so happens that opiates have the same chemical structure as the body's endogenous opioids. These opiate receptors either slow down or inhibit the activity of the neurons that contain them.

      As was explored earlier, opiates work on the brains reward system to provide pleasure.  Opiates increase the activity of the dopamine-containing neurons of the VTA.  The dopamine containing neurons of the VTA are under tight control.  These neurons receive both inhibitory and excitatory signals and the sum of these signals determines whether or not the neuron will fire and the rate at which the neuron fires.  Another group of neurons regulates the neurons of the VTA by producing the neurotransmitter gamma-aminobutyric acid (GABA).  When these regulatory neurons are active, they inhibit dopamine neurons causing a reduced release of dopamine.  These GABA receptors contain opiate receptors.  When opiates bind to these receptors, they prevent the GABA neurons send fewer inhibitory signals to the dopamine neurons.  The dopamine neurons then are free to release more dopamine from their axon terminals in the nucleus accumbens.  In addition, the neurons of the nucleus accumbens that are across from the synapse from the axon terminals of the dopamine-releasing neurons also contain opiate receptors.  As a result opiates can act directly on the nucleus accumbens and can thus produce reward.

Short Term Effects of Heroin Use

Long Term Effects of Heroin Use Medical Complications of Chronic Heroin Use
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Psychology, Sociology, Treatment