title: Changes of proenkephalin and prodynorphin mRNAs and related peptides in rat brain during the development of deep prepyriform cortex kindling.
abstract: The effects of deep prepyriform cortex (DPC) kindling on the amount of proenkephalin and prodynorphin mRNAs, Met5-enkephalin (ME) and dynorphin (DYN) in rat brain were examined. Animals received electrical stimulation of the DPC until two consecutive stage 2 seizures (S2) or stage 5 seizures (S5) were attained. The proenkephalin mRNA and ME contents in the entorhinal cortex were increased 24 h after S2 and also 5 min and 24 h post S5. In the hippocampus, the proenkephalin mRNA level was reduced 24 h after S2 but increased 5 min and 24 h after S5. Elevated hippocampal ME concentration was observed 24 h after S2 and S5. Similarly, the ME level in the frontal cortex was increased 24 h after S2 and S5 but the proenkephalin mRNA content was only elevated at S5. In the striatum, the proenkephalin mRNA level was slightly increased 24 h after S2 and S5, but no change in ME content was found. The amount of prodynorphin mRNA in the hippocampus was attenuated only at 24 h after S5, whereas DYN concentration was reduced 5 min after S5. No change in striatal DYN concentration was observed despite a slight elevation of prodynorphin mRNA 24 h post S2 and S5. Six weeks after the last seizure, no difference in ME and DYN was found between kindled and control animals. These findings indicate that the enkephalin-containing perforant pathway in the entorhinal cortex-hippocampal region is particularly sensitive to electrical stimulations applied to the DPC. Its role and importance in the development of kindling are discussed.
authors.affiliation: Laboratory of Molecular and Integrative Neuroscience, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
authors.forename: P H
authors.initials: PH
authors.lastname: Lee
authors.forename: D
authors.initials: D
authors.lastname: Zhao
authors.forename: C W
authors.initials: CW
authors.lastname: Xie
authors.forename: J F
authors.initials: JF
authors.lastname: McGinty
authors.forename: C L
authors.initials: CL
authors.lastname: Mitchell
authors.forename: J S
authors.initials: JS
authors.lastname: Hong
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002540:Cerebral Cortex / Q000378:metabolism* / Q000503:physiopathology; D004558:Electric Stimulation; D004745:Enkephalins / Q000378:metabolism*; D007696:Kindling, Neurologic; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D004745:Enkephalins; D009479:Neuropeptides; D011498:Protein Precursors; C029992:proenkephalin; C033660:preproenkephalin