Long-term effects of diazepam and phenobarbital treatment during development on GABA receptors, transporters and glutamic acid decarboxylase.
Diazepam (DZ) and phenobarbital (PH) are commonly used to treat early-life seizures and act on GABAA receptors (GABAR). The developing GABAergic system is highly plastic, and the long-term effects of postnatal treatment with these drugs on the GABAergic system has not been extensively examined. In the present study, we investigated the effects of prolonged DZ and PH treatment during postnatal development and then discontinuation on expression of a variety of genes involved in GABAergic neurotransmission during adulthood. Rat pups were treated with DZ, PH or vehicle from postnatal day (P) 10-P40 and then the dose was tapered for 2 weeks and terminated at P55. Expression of GABAR subunits, GABAB receptor subunits, GABA transporters (GAT) and GABA synthesizing enzymes (glutamic acid decarboxylase: GAD) mRNAs in hippocampal dentate granule neurons (DGNs) were analyzed using antisense RNA amplification at P90. Protein levels for the alpha1 subunit of GABAR, GAD67, GAT1 and 3 were also assessed using Western blotting. At P90, mRNA expression for GAT-1, 3, 4, GABAR subunits alpha4, alpha6, beta3, delta and theta and GABAB receptor subunit R1 was increased and mRNA expression for GAD65, GAD67 and GABAR subunits alpha1 and alpha3 were decreased in DGNs of rats treated with DZ and PH. The current data suggest that prolonged DZ and PH treatment during postnatal development causes permanent alterations in the expression of hippocampal GABA receptor subunits, GATs and GAD long after therapy has ended.
Raol
Y H
YH
Division of Neurology, Pediatric Regional Epilepsy Program, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Zhang
G
G
Budreck
E C
EC
Brooks-Kayal
A R
AR
D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D018891:Dentate Gyrus / Q000166:cytology / Q000254:growth & development; D003975:Diazepam / Q000494:pharmacology*; D018757:GABA Modulators / Q000494:pharmacology*; D050485:GABA Plasma Membrane Transport Proteins; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D005968:Glutamate Decarboxylase / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008297:Male; D026901:Membrane Transport Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010634:Phenobarbital / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018079:Receptors, GABA / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013995:Time
D018757:GABA Modulators; D050485:GABA Plasma Membrane Transport Proteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D018079:Receptors, GABA; C493415:Slc6a1 protein, rat; D005968:Glutamate Decarboxylase; D003975:Diazepam; D010634:Phenobarbital