REACTIVE ASTROCYTES EXPRESS SUBSTANCE-P IMMUNOREACTIVITY IN THE ADULTFOREBRAIN AFTER INJURY

TRANSFORMATION of normal resting astrocytes to reactive astrocytes aft er injury is a well-known phenomenon. Using immunofluorescent labellin g methods, astrocytes in the ischemically and retrogradely/anterograde ly damaged adult forebrain nuclei were shown to express substance-P im munoreactivity. In contrast, astrocytes were not immunostained for sub stance-P in the normal brain or undamaged areas. Since substance-P has been shown to regulate inflammatory, wound-healing and immune respons es in the peripheral tissues, it is likely that this aberrant expressi on of substance-P immunoreactivity in reactive astrocytes may relate t o similar functions in the central nervous system as in the peripheral tissues after injury.