Neurokinin-1 receptor mRNA expression differences in brains of HIV-infected individuals

The neurokinin-1 receptor, a G-protein coupled receptor, is present in cells of the nervous system and the immune system. Utilizing our recently developed SYBR green-based RT-PCR, we quantified full-length and truncated NK1R mRNA expression in the cingulate cortex and cerebellum of autopsy brains from HIV-negative and -positive individuals. In the cingulate cortex, the expression of the full-length NK1R was greater in HIV-negative individuals (n=3) in comparison to HIV-positive individuals (n=21; p-value=0.026). There were no observed differences in expression of the truncated NK1R in the cingulate cortex between HIV-positive and -negative individuals. The expression of NK1R isoforms, both truncated and full-length, was similar between HIV-negative and -positive individuals in the cerebellum. It was not possible to directly relate the magnitude of NK1R expression to impairment in neuropsychological impairment in this small cohort and none of the subjects had HIV encephalopathy. These preliminary data support the concept that the full-length form of NK1R may have important significance in cognitive functions and deficiency of this isoform may be relevant in neurologic and psychiatric manifestations of neuroAIDS.