title: Kindling induced changes in parvalbumin immunoreactivity in rat hippocampus and its relation to long-term decrease in GABA-immunoreactivity.
abstract: The immunoreactivity of parvalbumin (PV), a Ca2+-binding protein present in a subpopulation of interneurons, was studied in the hippocampal CA1 region during kindling epileptogenesis, induced by tetanic stimulation of the Schaffer collateral/commissural fibers. PV-immunoreactivity was increased in comparison to controls after 13 afterdischarges and after the induction of generalized seizures. A quantification of the number of PV-immunoreactive somata showed an increase of 20% in both stages of kindling. This level had returned to baseline level 31 days after the last seizure. These results imply that changes in PV-immunoreactivity are related to seizure activity rather than to the long-term increase in seizure sensitivity in kindled animals. Co-localization study in controls showed that 32% of PV-immunoreactive somata were also immunopositive for GABA. A colocalization study in stratum oriens and pyramidale on the stimulated side of kindled animals 31 days after the last generalized seizure showed neither a reduction in the number of PV-immunoreactive somata nor in the number of GABA-immunopositive cell bodies that co-localized with PV. In contrast, the number of GABA-immunoreactive somata that did not co-localize with PV was reduced by 50%. It has been shown that a large influx of Ca2+ plays a crucial role in epileptogenesis. Here we demonstrate that the presence of the calcium-binding protein parvalbumin seems to exert a protective effect against the process that leads to a decrease in GABA content.
authors.affiliation: University of Amsterdam, Department of General Zoology, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: Kamphuis
authors.forename: E
authors.initials: E
authors.lastname: Huisman
authors.forename: W J
authors.initials: WJ
authors.lastname: Wadman
authors.forename: C W
authors.initials: CW
authors.lastname: Heizmann
authors.forename: F H
authors.initials: FH
authors.lastname: Lopes da Silva
mesh_terms: D000818:Animals; D006624:Hippocampus / Q000378:metabolism* / Q000503:physiopathology; D007150:Immunohistochemistry; D007696:Kindling, Neurologic; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000378:metabolism* / Q000503:physiopathology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D009124:Muscle Proteins; D010320:Parvalbumins; D005680:gamma-Aminobutyric Acid