Neurokinin (NK)-1 receptor expression in monocytes from bipolar disorder patients: A pilot study

Abstract Background Neurokinin 1 receptors (NK-1R) have been involved in several psychiatric disorders including major depression, but less is known for bipolar disorder (BD). Method We compared NK-1R expression and Substance P (SP) ability to induce NF-κB activation in monocytes from BD patients and healthy donors (HD), also looking for the effects of tobacco smoke. After informed written consent, 20 euthymic BD patients, either bipolar type 1 (BDI) or type 2 (BDII), and 14 age-matched healthy donors (HD) were enrolled. NK-1R expression in monocytes was evaluated by Western blot and expressed as the ratio between NK-1R and Na + /K + -ATPase protein expressions. NF-κB activation was assessed by measuring the nuclear content of the p50 subunit (ELISA kit). Results NK-1R expression was significantly reduced ( P P Limitations As a pilot study enrolling 20 BD patients, an obvious limitation is the sample size. Conclusions Our results show the existence of a relevant alteration in NK-1R expression in BD patients and further suggest SP involvement in BD, so improving our understanding of the underlying mechanisms of this disease.