Depression in Parkinsonʹs Disease Is Not Accompanied by More Corticotropin-Releasing Hormone Expressing Neurons in the Hypothalamic Paraventricular Nucleus

Background:Depression is frequently encountered in Parkinsonʹs disease (PD). In addition, more than half of the PD patients have a disturbed dexamethasone suppression test, which is associated with increased activity of corticotropin-releasing hormone (CRH) neurons. We recently found an increase in CRH neuron number, CRH-messenger RNA, and vasopressin colocalization in CRH neurons in the paraventricular nucleus (PVN) of depressed patients, which may be involved in the pathogenesis of depression. Methods:The number of neurons expressing CRH was determined in the PVN of 6 depressed PD patients with a high score (≥ 13) on the Hamilton Depression Rating Scale, 6 nondepressed PD patients, and 6 controls. Results:The three groups did not differ in the number of neurons expressing CRH. Conclusions:We hypothesize that activation of CRH neurons in the PVN, as we recently observed in idiopathic depression, does not play an essential role in depression in PD.