title: Autoradiography of L-type and N-type calcium channels in aged rat hippocampus, entorhinal cortex, and neocortex.
abstract: The present study examined brains from 6, 17, and 32 month old male (F344x BN)F1 rats to determine whether there was any age-related change in the distribution or density of L-type and N-type Ca2+ channels in hippocampus, entorhinal cortex, and neocortex, areas commonly involved in the generation of epileptic seizures. The L-type channel antagonist PN200-110 and the N-type channel antagonist omega-conotoxin GVIA were used to determine specific binding densities and the autoradiographic distribution of ligand binding was quantified by computer-assisted densitometry. One-way ANOVA noted a significant variance in the mean value of binding density between different age groups only in neocortex laminae IV-VI for [(3)H]PN200-110 binding (P < 0.05). Post-hoc testing indicated that the mean value of the 17 month old group was significantly less than those of the 6 and 32 month old groups (P < 0.05). These results indicate no overall age-related change in the number of L-type and N-type Ca2+ channels in brain areas frequently involved in seizure activity and suggest that age-related changes in brain Ca2+ physiology may be associated with changes in voltage-gated Ca2+ channel function rather than channel number.
authors.affiliation: Department of Neurology, Allegheny General Hospital, 940 South Tower, 320 E. North Avenue, Pittsburgh, PA 15212-4772, USA. kelly@wpahs.org
authors.forename: K M
authors.initials: KM
authors.lastname: Kelly
authors.forename: A
authors.initials: A
authors.lastname: Kume
authors.forename: R L
authors.initials: RL
authors.lastname: Albin
authors.forename: R L
authors.initials: RL
authors.lastname: Macdonald
mesh_terms: D000367:Age Factors; D000818:Animals; D001345:Autoradiography; D002121:Calcium Channel Blockers / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000378:metabolism*; D018728:Entorhinal Cortex / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D017275:Isradipine / Q000378:metabolism; D008297:Male; D019579:Neocortex / Q000378:metabolism*; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344; D020960:omega-Conotoxins / Q000378:metabolism
chemical_list: D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; D020960:omega-Conotoxins; D017275:Isradipine