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Apomorphine (Apokyn, Ixense, Spontane, Uprima) is a non-selective dopamine agonist which activates both D1-like and D2-like receptors, with some preference for the latter subtypes. It is historically a morphine decomposition product by boiling with concentrated acid, hence the -''morphine'' suffix. Apomorphine does not actually contain morphine or its skeleton, nor does it bind to opioid receptors. The ''apo''- prefix relates to it being an aporphine derivative. Historically, apomorphine has been tried for a variety of uses including psychiatric treatment of homosexuality in the early 20th century, and more recently in treating erectile dysfunction. Currently, apomorphine is used in the treatment of Parkinson's disease. It is a potent emetic (''i.e.'', it induces vomiting) and should not be administered without an antiemetic such as domperidone. The emetic properties of apomorphine are exploited in veterinary medicine to induce therapeutic emesis in canines that have recently ingested toxic or foreign substances. It was also successfully used as an unofficial treatment of heroin addiction, a purpose for which it was championed by the author William S. Burroughs. A recent study indicates that apomorphine might be a suitable marker for assessing central dopamine system alterations associated with chronic heroin consumption. There is, however, no clinical evidence that apomorphine is an effective and safe treatment regimen for opiate addiction. Early studies involved aversion therapy in alcoholism and anxiety, and modern reports are anecdotal.〔Dent JY (1949). "Apomorphine Treatment of Addiction." ''British Journal of Addiction to Alcohol & Other Drugs'' 46 (1); 15-28. () 〕 ==Biological Effects== Apomorphine is an agonist, or activator, of both D1 and D2 type dopamine receptors with a preference toward the D2 group. The members of the D2 subfamily, consisting of D2, D3, and D4 receptors, are involved with inhibitory neurotransmission. Inhibition is achieved through a signaling pathway in which the activated receptor, a G protein–coupled receptor, inhibits the enzyme adenylate cyclase, therefore decreasing the levels of the signaling molecule cyclic AMP. The D4 receptor in particular is an important target in the signaling pathway, and is connected to several neurological disorders. Shortage or excess of dopamine can prevent proper function and signaling of these receptors leading to disease states. It is classically thought that an excess of dopamine stimulation is a factor in schizophrenia, but it appears this relationship is pathway dependent and just one of several contributing factors. Apomorphine is useful in diseases where dopamine levels are lower than normal, such as Parkinson’s disease, and can help to restore proper motor behavior by increasing the inhibitory signaling. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Apomorphine」の詳細全文を読む スポンサード リンク
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