L-Dopa andthenegative symptomsofParkinsonism

Ithasbeenproposed that theneurological abnormalities ofParkinsonism canbedivided intopositive andnegative symptoms(Martin, 1967). Positive symptoms areconsidered toberelease phenomena. Pathological changes within oneregion ofthe central nervous system result intherelease ofthis region's control overasecond region. Thepositive symptoms arefelt toberelated tothephysiological dysfunction inthis second region. Thisresults from thelossofthenormalinhibition ofthisstructure. Examples ofpositive symptomsaretremor andrigidity. Negative symptomsarethought tobedueto disease ofastructure resulting inloss ofitsnormal function. Negative symptomsinclude difficulty withpostural fixation andrighting reflexes and akinesia. InhumanswithParkinsonism, ithasbeen proposed that 'the degree ofdamage inthepallidum issufficient toaccount foralltheloss ofpostural reflexes' (Martin, 1967). Thepurpose ofthis communication istoreview thevalidity andusefulness oftheaboveclassification ofsymptoms inrelation toclinical investigations withthedrug L-dopa. PHARMACOLOGY