Effects of age on pilocarpine-induced c-fos expression in rat hippocampus and cortex.
The effect of age on pilocarpine-induced expression of the immediate-early gene c-fos was examined in the hippocampus and cortex of Long-Evans rats. Rats were treated with either pilocarpine (25 mg/kg) or saline, and sacrificed 90 min. following injection. The level of c-fos mRNA and Fos-like protein expression was determined using in situ hybridization histochemistry, and immunocytochemistry, respectively. In saline-treated animals, comparable levels of c-fos mRNA and Fos-like protein were observed in the hippocampus and cortical regions of young (6 month) and aged (24-26 months) rats. The expression of Fos-like protein following pilocarpine treatment was increased, however, in frontal, retrosplenial, and cingulate cortex of aged compared to young rats. In frontal and retrosplenial cortex, the changes in Fos-like protein were accompanied by changes in c-fos mRNA expression. In contrast, no age difference was detected in the hippocampus or parietal cortex of pilocarpine-treated rats. These regionally-specific age differences in response to pilocarpine administration suggest that mechanisms localized to those areas play an important role in determining the response to cholinergic stimulation mediated through post-synaptic muscarinic receptors.
Bucci
D J
DJ
Neurobiology, University of North Carolina, Chapel Hill 27599, USA.
Rosen
D L
DL
Gallagher
M
M
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D010862:Pilocarpine / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects
D018679:Cholinergic Agonists; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D010862:Pilocarpine