The effects of acute methamphetamine administration on expression of the nuclear transcription factor NGFI-B mRNA and its co-localization with c-Fos immunoreactivity in the striatum were evaluated in animals receiving a single dose of methamphetamine (4 mg/kg) given at 2 or 6 hours prior to perfusion. All animals received a daily saline injection during six days prior to methamphetamine treatment. We have found that, similarly to c-Fos activation, NGFI-B mRNA levels were significantly increased two hours after methamphetamine treatment and returned to basal levels six hours later. Induction of NGFI-B mRNA levels by methamhetamine was highest in central striatum as compared to the dorsomedial distribution pattern observed in control animals. After acute methamphetamine treatment, the distribution pattern of NGFI-B mRNA upregulation was very similar to that of methamphetamine induced c-Fos immunoreactivity. However, co-localization studies with c-Fos immunoreactivity showed that not all NGFI-B positive cells contained c-Fos after methamphetamine treatment. Forty five percent of all NGFI-B mRNA expressing neurons contained c-Fos immunoreactivity in the dorsomedial striatum as compared to sixty percent in central and thirty five percent in ventrolateral striatum. This study provides a detailed description of the differential spatial and temporal modulation of NGFI-B and c-Fos expression in the striatum by acute methamphetamine treatment over time.
