Physician's responsibility for patients with epilepsy

✍ Scribed by David S. Bachman

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 116 KB
• Volume: 6
• Category: Article
• ISSN: 0364-5134
• DOI: 10.1002/ana.410060326

✦ Synopsis

decrease somewhat [2]. The number of presynaptic dopamine receptors, however, drops by 20 to 25% after long-term amphetamine or apomorphine administration [2], as indicated by a significant reduction in the specific binding of 3H-apomorphine in rat striatum [2]. Since presynaptic dopamine receptors operate by inhibiting the release of dopamine, this diminished number of presynaptic receptors would permit more release of dopamine, accounting for dopaminergic "sensitization" by long-term agonists.

It is reasonable to conclude, therefore, that loss of the L-dopa effect with chronic use is due to desensitization of postsynaptic neuroleptic/dopamine receptors and that withdrawal of L-dopa would permit rehypersensitization of these postsynaptic dopamine receptors [I]. Dyskinetic movements seen early in the treatment of Parkinson disease may be due to postsynaptic dopaminergic supersensitivity, whereas dyskinesias seen with chronic L-dopa therapy and other dopaminergic agents are due to loss of inhibition by presynaptic dopamine receptors.