Turkish Journal of Geriatrics 1999 , Vol 2, Issue 4
Ceyda GÜLTER, Ferhan GİRGİN, Gülinnaz ALPER, Mert ÖZGÖNÜL, Gülriz MENTEŞ, Biltan ERSÖZ
Ege Üniversitesi Tıp Fakültesi, Biokimya Anabilim Dalı, İzmir The process of aging is becoming increasingly important as the average longevity of the population increases and the number of people with both age-associated impairment and neurodegenerative diseases of old age rises sharply. The disturbed integrity of dopaminergic, noradrenergic and serotonergic neurons is considered to be the key in the impairments seen during aging and certain diseases. Underlying of the mental and motor changes observed in the elderly population, biogenic amines seem to play an important role. Monoamine oxidase(MAO) is an enzyme responsible for the inactivation of these biologically important active amines. it is one of the most investigated enzyme presumably because of its importance in biological psychiatry. The activity of MAO displays great variances in different organs during the process of aging and in the physiopathology of certain neurodegenerative diseases. Thus in the recent years, MAO inhibition is a widely used therapeutic strategy in the treatment of Alzheimer's disease, Parkinson's disease and depression seen in the elderly. The aim of our study was to determine the changes in biogenic amines. adrenalin (A), noradrenalin (NA): serotonin (5-HT), dopamine (DA), as well as in their metabolites, normetanephrine (NMN), homovanillic acid (HVA), dihydroxyphenyl acetic acid (DOPAC), 5-hydroxyindol acetic acid (5-HİAA) occurring concurrently with the changes in MAO activity of the prefrontal cortex of aging rats. We aimed to observe the effects of MAO inhibitors on altered levels of biogenic amines and their metabolites. in the first part of this study MAO activity and the levels of biogenic amines and their metabolites were measured in the prefrontal corticies of young (2-3 months old, n=15) and aging (16-18 months old, n=15) rats. in the second step, after chronic administration of deprenyl, MAO-B inhibitor, (0.25 mg/kg/day, 14 days, I.P) the above mentioned parameters were measured in the prefrontal corticies of young (2-3 months old. n = 10) and aging (16-18 months, n=10) rats. The results showed that MAO activities in prefrontal cortex were significantly higher in the aging groups (p=0.05). As for the biogenic amines elevated levels of noradrenaline and dopamine (respectively p=0.03,p=0.009); for the metabolites elevated levels of normetanephrine, homovanillic acid and dihydroxyphenyl acetic acid were found in the aging groups (respectively p=0.006, p=0.001, p=0.05). Administration of MAO inhibitor resulted in no difference in the levels of biogenic amines between placebo and deprenyl groups in neither young nor aging groups. However MAO activities were significantly decreased (respectively %65, %76). Keywords : Aging, Prefrontal cortex, Biogenic amines, Monoamine oxidase, High performance liquid chromatography