Drugs that excite bodily functions, especially those that excite the brain and central nervous system, are called stimulants. Nicotine (though nicotine is thought to act both as a short-term stimulant and as a long-term depressant) and the ingredients in many diet pills are considered stimulants. There are two main types of nervous-system stimulants: those that make the user feel more alert and energetic and have only minor effects on the emotions and those that affect emotions. These are usually called antidepressants. Stimulants may be used medically to cope with sleep disorders, to control appetite, or to fight depression. Some, however, take certain stimulants simply to achieve a feeling of eupshoria or to relieve boredom or tension. There are many groups of stimulants. On of these is the tricyclic antidepressant drug group has extremely effective in treating depressed patients. A common, naturally occurring group of stimulants is the methylxanthines. This group includes caffeine, theophylline, and theobromine--the active ingredients of coffee, tea, cocoa, and cola beverages. The strongest of these stimulants is caffeine. For many persons it produces a clear and more rapid flow of thought and helps to rid of drowsiness and fatigue or tiredness. It may be used to treat respiratory depression and, because it constricts blood vessels in the brain, it is often an ingredient in headache medicines. In some instances caffeine can cause over stimulation, headaches, heart palpitations, and insomnia. This information relates to our project because we are testing the effect of nicotine on the regeneration of planaria. |
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