Central nervous system, drugs acting responses

The generic name of the cacao tree (Theobroma) means food of the Gods and gives its name to a caffeine-like stimulant, theobromine (a methylxanthine). It has been claimed that the theobromine in chocolate is responsible for its addictive characteristics. This is based on the fact that methylxanthines bind to adenosine receptors in the central nervous system and act as antagonists to this neurotransmitter (Chapter 14). However, another group of substances, the amides formed between ethanolamine and unsaturated fatty acids, are also possible candidates for the title of the chocolate drug . 

Drugs that act on the central nervous system appear to produce an exaggerated response in relation to that expected from the plasma concentration, and sedatives and hypnotics may have a pronounced hangover effect. These drugs are also more likely to depress respiration because vital capacity and maximum breathing capacity are lessened in the elderly. 

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