Neuropharmacology

Biography

Biography: Dario Furnari

Abstract

Aging (or senescence) isthatperiod of life, characterized by a series of progressive irreversiblechangesaffecting the cells, tissues and organs, therefore of the wholeorganism, whichbeginwhenthis, once developmentis complete, hasreached aadulthood, and continue to manifestthemselves, culminating in death, whichoccursas a consequence of them and not by the intervention of externalfactors.
Gerontologyis the biological discipline thatstudiesthisprocess, which can be consideredbothphysiological, becauseitisnormallypresent in the life span, and pathologicalbecauseitcausesdisturbances.
The senile alterations, found in manyorgans are quitedistinct from the pathologiesaffecting the elderly; the branch of medicine, calledGeriatrics, deals with the study of thesewhoseappearanceiscertainlyfacilitated by the modificationscaused by aging.Lifespan:Thereduction in life spanseems to always be due to a greater production of free radicals (definedas ROS = ReactiveOxygenSubstances).
In reality, a certainamount of ROS isphysiologicallyformed in the body'scells, hence the excessive production of these or theirpoorelimination, hasbeenconsideredone of the mostsignificantcauses of aging due to the factthatthese free radicalsinteract withnucleicacids, proteins and lipids, alteringthemstructurally and functionally.the onlycellsthat can have a maximum life spanequal to that of the organism to whichtheybelong are perennial or post mitoticcells (neurons and musclecells), thatis, thosewithout replicative activity.
Certainlynotallperennialcells live as long as the organism, aswelldemonstrated by the factthat the weight of the human brain, whichis 1500 g at the age of 30, decreases on average to 1390 g at the age of 90 years due to the programmeddeaththataffects a large number of neurons.
Itiscurrentlyestablishedthat labile and stablecellsafterhavingperformed a certainnumber of mitoses in the culture medium, experienceagingphenomena, which prelude to death by apoptosis.
"In vivo" the mostimportantcellularchangesthatoccur in senescenceconsist in hypotrophy, whichismainlyreflected in the reduction of musclemasses, and in the accumulation inside the cells and also in the intercellularspaces of harmfulmaterials: lipofucsins, substanceamyeloid and metals.Physiologicalfunctions in general improve from birth to 30 years of age, then a declinebegins, variablebetween the variousfunctions, whichiscloselylinked to lifestyle.
Amongthesefunctions the mostimportant:
Musclestrength
Nervousfunction
Respiratoryfunction
Cardiovascularfunction
Bone mass

Normallythereis a continuousremodeling of the motorunits, in particularat the level of the neuromuscularplaque. The remodelingprocessinvolvesatrophy and thereforeeffectivedenervation on the onehand, butat the same time, the development of new axonicterminals. With age, the denervationmechanismprevails over the regenerativeone, whichinducesmuscleatrophy with irreversiblealterations, in particular for type II musclefibers.
The reduction in muscle mass and strengththereforeresults from the association of twofactors, on the onehand the atrophy of musclecells and on the other the reduction of dailyactivity.
Itisproventhat in elderlysubjects a regular musclestrengtheningactivitypromotesproteinanabolism and slows down the inevitablereduction in muscle mass and strength.
Resultsdemonstrate a greatability to respond to the training stimulusalso in elderlypeople, whichinvolvesprocesses of synthesis and neuromotorplasticityeven in 80-year-old subjects.The cumulative effects of aging of the centralnervoussystem are linked to a 37% reduction in the number of spinalnervefibers and a 10% reduction in the speed of conduction of excitementalong the fibers.
The execution time of relativelycomplexmovementsisgreater in elderlysubjectsthan in youngpeople, with the samedailyphysicalactivity.
Observationssuggestthatmaintaining a physicallyactivelifestylefacilitatesgoodpreservation of neuromuscularfunction.Osteoporosisrepresents the mainproblem of aging, especially in womenafter menopause.The picture of osteoporosisinvolves the progressive demineralization of the boneswhichthereforebecomevery fragile.For people over 60, the reduction in bone mass can be 30-50%.
Weight lifting can counteractthisphenomenon.