Figure 3.

P2X7 receptor (P2X7R) is present on astrocytes in the parenchyma of secondary progressive multiple sclerosis (SPMS) frontal cortex. Confocal analysis of SPMS frontal cortex parenchyma shows absence of colocalization of P2X7R (red) with P2Y12R [(A), green], major histocompatibility complex II (MHC II) [(B), blue], and myelin basic protein [(C), blue], but the presence of merged P2X7R/glial fibrillary acidic protein signals (D–F). P2X7R/MHC II-positive signal is also visible but confined in the lumen of a blood vessel [(B), arrow, pink]. Immunohistochemistry analysis of cortical parenchyma reveals the abundant presence of P2X7R in GM on interlaminar (G) and protoplasmic astrocytes (E), and in white matter on fibrous astrocytes (I,J). In (J), astrocytic “vascular feet” are visible adjacent to the blood vessel walls (arrows).