Heroin

Endorphins

-Combat pain -The big difference between them and the opiates is that the body produces the endorphins itself, and quickly breaks them down after they are released. That means there is little risk of addiction. In terms of evolution, endorphins are important for survival. If you need to flee after sustaining an injury, endorphins can ease the pain.

Addiction

Continuous use of heroin reduces your body's ability to release dopamine in a natural way. -You are no longer able to feel pleasure without drugs. That makes you want to take more heroin immediately.

Pleasure Heroin Condition

Alters these normal conditions: 1. Heroin is converted in the body into morphine. Morphine mimics endorphins and binds tightly to the receptors of the GABA neuron. This inhibits the release of GABA. 2. As the supply of GABA diminishes, the dopamine neuron can release more dopamine. It stimulates the reward centre and you feel pleasure. 3. In comparison to endorphins, morphine is broken down very slowly. The slow breakdown of morphine allows the pleasure process to continue. The release of dopamine remains excessively high, and the pleasant feelings persist longer. 4. The naturally occurring endorphins are not addictive because they are immediately broken down after binding to the receptors. They do not stay in contact with the receptors long enough to induce tolerance. Morphine binds to dopamine neuron, but can no longer keep release of dopamine under control

Pain Heroin Condition

Heroin is converted in the body into morphine. Morphine first acts identically to endorphins. The morphine binds to the receptors on the axon of the substance P neuron and blocks the release of substance P. The pain signal can no longer be relayed. -Morphine goes one step further. It also blocks the receptors on the adjacent neuron from receiving substance P. Any substance P that is now released has nowhere to bind. It can no longer do its work. -The morphine leaves the receptor and is slowly broken down. The big difference between heroin and endorphins is that heroin works far better and longer than the endorphins. Endorphins are produced by the body itself and are broken down very quickly. That means there is no risk of addiction.

Vomiting

Heroin stimulates the vomiting centre in the brain. When people take opiates, they often experience nausea and vomiting, especially in the beginning.

Coughing

Heroin suppresses the cough centre in the brain. This why other opiates (like codeine) are used in coughing syrup.

Heroin and the brain

Opiates are powerful drugs used as narcotics. Opiates include compounds like heroin, morphine and codeine. -The most significant effects of taking heroin are pleasure, pain relief and the suppression of breathing. -Human body contains receptors to which opiates can bind. But the body also produces substances of its own called endorphins, which can bind to these receptors -When heroin is taken, it converted into morphine in the body. The effects of heroin derive from the fact that morphine mimics endorphins, the natural neurotransmitters. -Both endorphins and morphine indirectly stimulate the brains reward centre, and that makes you feel pleasant. Morphine also inhibits the release of substance P. Substance P plays a role in the transmission of pain signals. The neurons that regulate breathing also contain opioid receptors. Morphine can bind to them too. -GABA inhibits release of dopamine

Breathing

Overdose = suffocation -Strongly affects breathing rhythm -Breathing system regulated by neurons in brain stem -Neurons receive info about the amounts of oxygen and carbon dioxide in blood -If shortage of oxygen/excess carbon dioxide, the neurons signal to breathing muscles to make them contract Heroin -Neurons that regulate breathing contain opioid receptors -Heroin - morphine, the morphine can bind to these receptors -Leads to suppression of signal transmission to breathing muscle / breathing = swallower -In overdose, suppression if breathing no longer possible

Normal condition

The dopamine neuron also contains opioid receptors. Endorphins bind not only to the GABA neuron but also to the dopamine neuron. In this case, the binding action inhibits the release of dopamine. Endorphins can therefore both stimulate and inhibit. Under normal conditions, they help to keep the system in balance.

Bowels

The gastro-intestinal system also contains a large number of opioid receptors. Heroin inhibits bowel activity. Heroin addicts often suffer constipation (in the past, opium was used to control diarrhoea).

Pleasure

The pleasant feelings from heroin arise because the reward centre is stimulated. The key neurotransmitter in the reward system is dopamine. If you take heroin, your body first converts the drug into morphine. Morphine mimics, or basically performs the same actions, as endorphins, the natural neurotransmitters. That means that bodily processes involving endorphins are imitated when you take heroin.

Pain Normal Conditions in Fighting Pain

The substance P neuron transmits pain signals by releasing substance P. The axon of the substance P neuron contains opioid receptors as well as substance P. -The substance P is stored in vesicles at the tip of the axon. -When a stimulus reaches the axon terminal, the vesicles fuse to the wall of the neuron. This releases substance P into the space (synapse) between two neurons. It binds to the receptors on the adjacent neuron. The binding action relays the pain signal further. -If the pain becomes too severe, the body tries to protect itself by releasing natural endorphins. The endorphins bind to the opioid receptors on the axon of the substance P neuron. This slows the relay of the pain signal. The endorphins then unbind from the receptor and are broken down immediately.

Neurons

Three types of neurons, or nerve cells, are involved in the pleasure or reward process: 1) endorphin neurons 2) GABA neurons 3) dopamine neurons

Eye pupils

Several areas in the brain regulate the pupillary opening in the eye. These areas contain many receptors for endorphins and opiates. That explains why heroin contracts the pupils to the size of pinheads.

Pain

Pain relieving effects -Special neurons in your fingers detect this and react by sending a pain stimulus to your spinal cord and brain. This stimulus is relayed many times from neuron to neuron on the way. The neurotransmitter substance P enables this process.