(+)-Methamphetamine increases corticosterone in plasma and BDNF in brain more than forced swim or isolation in neonatal rats.
(+)-Methamphetamine (MA) administered on postnatal days (P) 11-15 (four times/day) results in increased corticosterone that overlaps the stress hyporesponsive period (SHRP; P2-14) and leads to later learning and memory deficits. Elevated corticosterone during the SHRP results in neurotrophin changes and long-term effects on learning. We determined whether two known stressors could mimic the effects of MA [10 (mg/kg)/dose] administration in neonatal rats. Stressors were four 15-min sessions of forced swim or isolation (confinement in forced swim tubes without water). Saline and weighed-only controls were included and all five treatments were represented within each litter. Corticosterone in plasma and brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in neostriatum and hippocampus were examined after one or four treatments on P11 or P15 (0.5, 1.75, 6.5, or 24 h after first dose). MA increased corticosterone and BDNF; forced swim and isolation also increased corticosterone, but to a lesser extent than MA, and neither stressor increased BDNF. NGF was unaffected by saline treatment, but there was a minor reduction in NGF in the forced swim group compared with the weighed-only group. The data show that MA is more potent at releasing corticosterone and increasing BDNF than short-term, repeated episodes of forced swim or isolation. The possible relationship between these changes and the long-term cognitive effects of developmental MA administration are discussed.
Grace
Curtis E
CE
Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, Ohio 45229-3039, USA.
Schaefer
Tori L
TL
Herring
Nicole R
NR
Skelton
Matthew R
MR
McCrea
Anne E
AE
Vorhees
Charles V
CV
Williams
Michael T
MT
D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003345:Corticosterone / Q000097:blood*; D005260:Female; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012934:Social Isolation; D013315:Stress, Psychological / Q000097:blood / Q000209:etiology / Q000473:pathology*; D013550:Swimming; D013997:Time Factors
D019208:Brain-Derived Neurotrophic Factor; D000697:Central Nervous System Stimulants; D008694:Methamphetamine; D003345:Corticosterone