Pentylenetetrazol-induced status epilepticus up-regulates the expression of glucose transporter mRNAs but not proteins in the immature rat brain

Abstract

Prolonged pentylenetetrazol (PTZ)-induced seizures increase cerebral energy demands in a region-specific manner. During PTZ seizures, cerebral glucose utilization increases over control levels in all brain regions at 10 days while 21-day-old rats exhibit increases, decreases or no change. To explore the effects of such acute changes in metabolic demand on the expression of glucose transporter proteins mediating glucose delivery to brain, we studied the consequences of PTZ seizures on GLUT1 and GLUT3 mRNAs and proteins between 1 and 72 h after seizure induction. At both ages, seizures induced a rapid up-regulation of GLUT1 and GLUT3 mRNAs which was prominent at 1 and 4 h, and was greater at 10 than at 21 days. By 24 h and 72 h, the levels of the mRNAs of the two transporter returned to control levels or were slightly down-regulated. The levels of GLUT1 and GLUT3 proteins were not affected by the seizures and only scattered decreases in GLUT3 protein were recorded, mainly in midbrain–brainstem areas. These data show that acute pentylenetetrazol seizures induce a rapid up-regulation of the GLUT1 and GLUT3 mRNAs, but do not result in measurable increases in protein levels, suggesting translational regulation.