BRIEF REPORT |
Correspondence to: P. Pompei, Dept. of Pharmacological Sciences & Experimental Medicine, University of Camerino, Camerino MC-62032, Italy. E-mail: pompei@cambio.unicam.it
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Summary |
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Preprotachykinin-A (PPT-A) mRNA levels in discrete rat brain regions were examined. Analysis of silver grains revealed a 19.2% and 31.5% statistically significant decrease in PPT-A mRNA in the dorsal and ventral caudate putamen (d-CPu and v-CPu), respectively, a 30% lower expression of PPT-A mRNA in the bed nucleus of the stria terminalis (BNST), a 33.7% decrease in PPT-A mRNA in the habenula (Hb), and a 30% decrease of PPT-A mRNA levels in the posterodorsal part of the medial amygdala (MePD). Results show that aging of the CNS is associated with widespread changes in tachykinin gene expression, suggesting that alterations in the tachykinergic system may have implications in the physiopathology of the elderly. (J Histochem Cytochem 49:13251326, 2001)
Key Words: aging, PPT-A, in situ hybridization, substance P
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Introduction |
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In humans, aging is associated with a range of structural and neurochemical changes that may reflect behavioral responding alterations. Tachykinins (Tks) are of some importance because they have been implicated in some degenerative, yet age-related conditions, such as Parkinson's and Alzheimer's disease (
Tks are widely distributed in the CNS (
In situ hybridization results were examined with a Nikon Optiphot-2 microscope. As depicted in Fig 1A, PPT-A mRNA levels in young rats were not statistically different from those of old rats in the mPOA, whereas pairwise comparisons showed a statistically significant difference between young and old rats in the d-CPu (p<0.05) and v-CPu (p<0.01), as well as in the BNST (p<0.01). PPT-A mRNA levels in the d-CPu were about 20% lower in old compared to young rats, and v-CPu and BNST showed a 30% decrease in PPT-A mRNA levels in old compared to young rats. Fig 1B shows PPT-A mRNA levels in Hb and MePD. Both areas highlighted an approximately 30% statistically significant decrease (p<0.01 in Hb or MePD) in their levels of PPT-A mRNA in old compared to young rats.
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This study shows significant changes in brain PPT-A mRNA levels during aging. PPT-A gene expression was markedly decreased in old compared to young rats in discrete brain areas, with special regard to the striatum.
Received for publication November 29, 2000; accepted February 16, 2001.
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