A 45-year-old woman, admitted to a psychiatric hospital, has been standing
immobile for several hours with one of his arm stretched upwards. The patient was
mute, unresponsive and did not appear aware of her surrounding. When placed in
another awkward posture the patient maintained that posture for a long time without
apparent distress. .Which of the following neurotransmitter has been consistently
implicated in the patient’s syndrome?
A. Norepinephrine B. Acetylcholine C. Histamine D. Dopamine E. GABA
Dopamine-answer: d(katzung, pp 463, koda-kimble, pp 78-3)the patient is most likely suffering from the catatonic subtype of schizophrenia which ischaracterized by motor immobility and abnormal posture maintained for a long time ( the socalled waxy flexibility). a number of theories related to major neurotransmitter systems hasbeen proposed to explain the symptoms of schizophrenia. of these, the dopamine hypothesisstates that the illness results from an excessive dopaminergic activity in mesolimbic andmesocortical pathways. the dopamine hypothesis is the most fully developed and is supportedby several lines of evidence, including the fact that most antipsychotic drugs block d2receptors and there is a very good correlation between clinical potency of these drugs andtheir in vitro affinity for these receptors. other two major hypotheses of schizophrenia are theserotonin hypothesis (it is known that alteration in serotonergic functioning affects multipleneurotransmitter systems), and the glutamate hypothesis that proposes a hypofunctionalglutamate system in schizophrenia.a, b, c, e) (see explanation above)