{"id":32625,"date":"2019-02-24T01:51:32","date_gmt":"2019-02-23T22:51:32","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=32625"},"modified":"2019-02-23T22:04:27","modified_gmt":"2019-02-23T19:04:27","slug":"32625","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/02\/24\/32625","title":{"rendered":"Zevk, sefa, ba\u011f\u0131ml\u0131l\u0131k: Bizi bu \u00f6strojen mahvetti"},"content":{"rendered":"

Kad\u0131nlar ve erkekler aras\u0131ndaki farklar herhalde g\u00fcndelik hayatta dilimize en s\u0131k dolad\u0131\u011f\u0131m\u0131z konulardan biridir. Oysa g\u00f6zlemledi\u011fimiz davran\u0131\u015f kal\u0131plar\u0131 ya yanl\u0131\u015f bir genellemeye kar\u015f\u0131l\u0131k gelir ya da b\u00fcy\u00fck \u00f6l\u00e7\u00fcde k\u00fclt\u00fcreldir, yani ba\u011flam\u0131na g\u00f6re de\u011fi\u015fir. Fakat bir fark var ki bu sohbetlere pek konu olmad\u0131\u011f\u0131 halde, ki\u015fisel kanaatlerle de\u011fil bilimsel deneylerle sabitlenecek kadar ger\u00e7ek: Kad\u0131nlar\u0131n alkol ve uyu\u015fturucu gibi zevk veren maddelere ba\u011f\u0131ml\u0131l\u0131k e\u011filimi\u2026 Bu c\u00fcmlenin devam\u0131n\u0131 \u00e7o\u011fumuz \u201cdaha d\u00fc\u015f\u00fck\u201d diye tamaml\u0131yor olabiliriz; oysa \u00e7al\u0131\u015fmalar a\u00e7\u0131k\u00e7a tam tersini g\u00f6steriyor. Kad\u0131nlar erkeklerden \u00e7ok daha h\u0131zl\u0131 ve g\u00fc\u00e7l\u00fc bi\u00e7imde ba\u011f\u0131ml\u0131 oluyor. Sebep daha \u00f6nce defalarca g\u00f6sterildi\u011fi \u00fczere \u00f6strojen! <\/span>Neuropsychopharmacology<\/span><\/i> dergisinin 23 Ocak say\u0131s\u0131nda yay\u0131mlanan bir \u00e7al\u0131\u015fma, alkol ve esrar kullan\u0131m\u0131n\u0131 ele alan ve benzer sonu\u00e7lara ula\u015fan daha eski tarihli \u00e7al\u0131\u015fmalara yeni verilerle destek \u00e7\u0131kt\u0131: Bu seferki keyif verici maddemiz kokain.<\/span><\/p>\n

Vanderbilt \u00dcniversitesi (ABD) ara\u015ft\u0131rmac\u0131lar\u0131 taraf\u0131ndan, erkek farelerle adet d\u00f6ng\u00fcs\u00fcn\u00fcn \u00e7e\u015fitli evrelerindeki di\u015fi farelerin kullan\u0131ld\u0131\u011f\u0131 bu son \u00e7al\u0131\u015fmada nispeten basit diyebilece\u011fimiz bir d\u00fczenek olu\u015fturulmu\u015f. Hayvanlar biri aktif di\u011feri pasif konumdaki iki d\u00fc\u011fmeden olu\u015fan bir kolla ba\u015f ba\u015fa b\u0131rak\u0131lm\u0131\u015f. Tahmin edilece\u011fi \u00fczere hayvan kolun aktif d\u00fc\u011fmesine bast\u0131\u011f\u0131nda kateter arac\u0131l\u0131\u011f\u0131yla tek doz kokaine maruz kalaca\u011f\u0131 bir pompaya ba\u011flanm\u0131\u015f. Uyu\u015fturucu \u00e7al\u0131\u015fmalar\u0131nda ya da klinik deneylerde maddenin kendisi kadar ki\u015fiye onu \u00e7a\u011fr\u0131\u015ft\u0131ran ortam ya da nesnelerin rol\u00fc de \u00f6nemsenir. Nitekim bu \u00e7al\u0131\u015fmay\u0131 \u00f6zel k\u0131lan ayr\u0131nt\u0131 tam da bu. D\u00f6rt k\u0131sma ayr\u0131lan deneyin ilk a\u015famas\u0131nda ba\u011f\u0131ml\u0131l\u0131k yaratmayacak d\u00fc\u015f\u00fck dozda kokain aktif d\u00fc\u011fmeye basan hayvanlara \u0131\u015f\u0131k e\u015fli\u011finde verilmi\u015f. Bazen de tam tersi, hayvanlar kokain olmadan \u0131\u015f\u0131k alt\u0131nda b\u0131rak\u0131lm\u0131\u015f. Ama\u00e7 \u0131\u015f\u0131k ile kokain aras\u0131ndaki Pavlovcu \u015fartlanman\u0131n oturtulmas\u0131. \u0130kinci a\u015famada hayvanlara, yine aktif d\u00fc\u011fmeye bast\u0131klar\u0131 \u00f6l\u00e7\u00fcde, \u0131\u015f\u0131k ya da benzeri herhangi bir i\u015faret e\u015flik etmeksizin kokain verilmi\u015f. Buradaki ama\u00e7 ise al\u0131\u015fkanl\u0131k geli\u015ftirmelerinin sa\u011flanmas\u0131. Ard\u0131ndan s\u0131ra deneyin kritik noktas\u0131na, yani di\u015fi ile erkek aras\u0131ndaki, hatta adet d\u00f6ng\u00fcs\u00fcn\u00fcn de\u011fi\u015fik evrelerindeki di\u015filer aras\u0131ndaki farkl\u0131l\u0131klar\u0131n ortaya kondu\u011fu \u00fc\u00e7\u00fcnc\u00fc a\u015famaya gelmi\u015f. Bu sefer kokain aktif d\u00fc\u011fmeye her bas\u0131\u015fta y\u00fcksek dozdan al\u00e7ak doza do\u011fru, ilk iki sefer \u0131\u015f\u0131ks\u0131z, \u00fc\u00e7\u00fcnc\u00fc ve d\u00f6rd\u00fcnc\u00fc sefer \u0131\u015f\u0131k e\u015fli\u011finde verilmi\u015f. Di\u011fer bir deyi\u015fle hayvanlar ba\u015flang\u0131\u00e7ta aktif d\u00fc\u011fmeye basman\u0131n y\u00fcksek dozda kokain almak i\u00e7in yeterli oldu\u011fu bir ortamdan, d\u00fc\u011fmeye basman\u0131n al\u0131nan \u00f6d\u00fcle de\u011fmeyece\u011fi dolay\u0131s\u0131yla \u00f6denen bedelin (yani harcanan \u00e7aban\u0131n) pahal\u0131la\u015ft\u0131\u011f\u0131 bir d\u00fczene\u011fin i\u00e7ine d\u00fc\u015f\u00fcr\u00fclm\u00fc\u015fler. Bu anlamda en y\u00fcksek bedeli kimin \u00f6deyece\u011fi, yani alaca\u011f\u0131 d\u00fc\u015f\u00fck doz kokaine ra\u011fmen d\u00fc\u011fmeye basma zahmetine katlanmaya kimin sonuna kadar devam edece\u011fi b\u00fct\u00fcn bir \u00e7al\u0131\u015fman\u0131n anlam buldu\u011fu noktay\u0131 olu\u015fturmu\u015f. Ve cevap, yukar\u0131da da belirtti\u011fimiz gibi, \u00f6strojen seviyesi tavan yapm\u0131\u015f evredeki di\u015filer!\u00a0<\/span>Son evrede kokainin kesildi\u011fi 1. ve 30. g\u00fcnlerde sadece \u0131\u015f\u0131k verilerek hayvanlar\u0131n verdi\u011fi tepkilerin g\u00f6zlenmesine, yani \u00e7a\u011fr\u0131\u015f\u0131m\u0131n motivasyon \u00fczerindeki etkisinin \u00f6l\u00e7\u00fcm\u00fcne s\u0131ra gelmi\u015f. \u0130lk g\u00fcn anlaml\u0131 bir fark g\u00f6r\u00fclmezken 30. g\u00fcn hepsi daha fazla istek g\u00f6stermi\u015f, yani \u00e7a\u011fr\u0131\u015f\u0131m yapan uyaran aktif d\u00fc\u011fmeye basma motivasyonunu hepsinde art\u0131rm\u0131\u015f. \u00d6zellikle de bir \u00f6nceki deney a\u015famas\u0131nda kokain ve \u0131\u015f\u0131\u011f\u0131 \u00f6strojeni y\u00fcksek seviyedeyken alan di\u015fi farelerde\u2026 <\/span><\/p>\n

Belirtti\u011fimiz gibi \u00f6strojenin bizi bizden alan etkilerini ortaya koyan ilk ara\u015ft\u0131rma de\u011fil bu. 2018\u2019in Ekim ay\u0131nda benzer bir \u00e7al\u0131\u015fma, Cagliari \u00dcniversitesi (\u0130talya) ara\u015ft\u0131rmac\u0131lar\u0131 taraf\u0131ndan esrar kullan\u0131m\u0131 ba\u011flam\u0131nda tekrarlanm\u0131\u015f ve yine ayn\u0131 sonu\u00e7lara ula\u015f\u0131lm\u0131\u015ft\u0131. Bu haberi okuyanlar\u0131n zihninde, elinde i\u00e7ki barda\u011f\u0131 ya da esrarl\u0131 sigara tutan binlerce erkek g\u00f6r\u00fcnt\u00fcs\u00fcne kar\u015f\u0131l\u0131k bir avu\u00e7 kad\u0131n\u0131nki canlanabilir. Fakat sosyo-k\u00fclt\u00fcrel bu durumun biyolojik ger\u00e7ekler a\u00e7\u0131s\u0131ndan bir \u00f6nemi yok. Asl\u0131nda erkeklerin cinsiyet hormonlar\u0131n\u0131n da davran\u0131\u015flar\u0131 \u00fczerinde belli bir etkisi var: Testosteronun risk-alma davran\u0131\u015f\u0131n\u0131 tetikleyerek beynin \u00f6d\u00fcl sistemini bask\u0131lad\u0131\u011f\u0131 biliniyor. Bu da onlar\u0131 \u00f6rne\u011fin esrar \u201cdenemeye\u201d d\u00f6rt kat daha yatk\u0131n hale getiriyor, hem de daha y\u00fcksek dozlarda. Gel g\u00f6r ki denemeye daha az hevesli kad\u0131nlar\/di\u015fi hayvanlar ilk seferden sonra \u00e7ok daha h\u0131zl\u0131 al\u0131\u015fkanl\u0131k geli\u015ftiriyorlar. Bir miktar i\u015fin biyolojisine girecek olursak, insan beynindeki, esrarda bulunan kanabinoid isimli kimyasal ile ayn\u0131 aileden gelen bir h\u00fccre a\u011f\u0131, endokanabinoid sistem, cinsiyet hormonlar\u0131ndan farkl\u0131 bi\u00e7imlerde etkilenir. Bu sisteme ait resept\u00f6rler erkekler ve di\u015filerde farkl\u0131 say\u0131larda ve hassasiyettedir. \u00d6strojen hormonunun direk etkiledi\u011fi sistemin nihai hedefinde ise zevk ve \u00f6d\u00fcl n\u00f6rotransmiteri olarak bilinen dopamin bulunur. Sonu\u00e7ta esrar\u0131n i\u00e7indeki kanabinoid, beyindeki endokanabinoid sistemini direk etkiledi\u011finde ortamdaki \u00f6strojen dopamin sisteminin daha h\u0131zl\u0131 atle\u015flenmesini sa\u011flar. Bu da al\u0131nan zevki art\u0131r\u0131r. <\/span><\/p>\n

Ayn\u0131 mekanizmaya ve benzer sonu\u00e7lara \u0130llinois \u00dcniversitesi ara\u015ft\u0131rmac\u0131lar\u0131 2017\u2019de, alkol \u00f6zelinde de ula\u015fm\u0131\u015ft\u0131. Bu \u00e7al\u0131\u015fmada da ara\u015ft\u0131rmac\u0131lar beynin \u00f6d\u00fcl merkezi denen, yine dopaminle ba\u011flant\u0131l\u0131, ventral tegmental alan (VTA) isimli bir b\u00f6lgesinden bahsetmi\u015flerdi.\u00a0<\/span>Ara\u015ft\u0131rmac\u0131lar\u0131n belirtti\u011fine g\u00f6re g\u00fczel oldu\u011fu d\u00fc\u015f\u00fcn\u00fclen bir maddeye, mesela \u00e7ikolataya rastland\u0131\u011f\u0131nda, VTA\u2019daki dopamin salg\u0131lay\u0131c\u0131 n\u00f6ronlar aktifle\u015fiyor ve \u00e7ikolatan\u0131n yenilesi oldu\u011fu fikrini peki\u015ftiren \u00f6d\u00fcl sistemini uyar\u0131yor. \u00d6yle ki zamanla iyice aktifle\u015fen VTA n\u00f6ronlar\u0131 \u00f6yle bir a\u015famaya ula\u015f\u0131yor ki s\u0131rf \u00e7ikolatan\u0131n g\u00f6r\u00fcnt\u00fcs\u00fc ve hatta d\u00fc\u015f\u00fcncesi bile ayn\u0131 etkiyi sa\u011flamaya yetiyor. T\u00fcm bu sefa d\u00fc\u015fk\u00fcnl\u00fc\u011f\u00fcn\u00fcn m\u00fcsebbibi ise hep ayn\u0131 yap\u0131: \u00f6strojen! Ara\u015ft\u0131rmac\u0131lar \u00f6strojen resept\u00f6rlerini bloke ettikleri durumlarda alkole verilen tepkinin belirgin bi\u00e7imde azald\u0131\u011f\u0131n\u0131 g\u00f6stermi\u015fler. Bu noktada ara\u015ft\u0131rman\u0131n y\u00fcr\u00fct\u00fcc\u00fclerinden gelen ilgin\u00e7 bir uyar\u0131 da var:\u00a0<\/span>\u201cAlkol\u00fcn a\u015f\u0131r\u0131 t\u00fcketildi\u011fi i\u00e7ki alemlerinin beyinde kal\u0131c\u0131 de\u011fi\u015fimlere neden oldu\u011fu biliniyor fakat \u00f6zellikle kad\u0131nlarda, alkol-VTA-\u00f6strojen etkile\u015fiminden dolay\u0131 bu de\u011fi\u015fimler daha h\u0131zl\u0131 ve belirgin olabiliyor. Beynin \u00f6d\u00fcl merkezi \u00e7ok g\u00fc\u00e7l\u00fc cevap verdi\u011finden kad\u0131nlar fark\u0131nda olmadan a\u015f\u0131r\u0131 i\u00e7tiklerinin bilincinde olmal\u0131lar.\u201d Sonu\u00e7ta kim ne kadar i\u00e7erse i\u00e7sin denilebilir, fakat ucunda ba\u011f\u0131ml\u0131l\u0131k ya da ba\u011f\u0131ml\u0131l\u0131\u011f\u0131n n\u00fcksetme riski varsa tercihimizi masum \u00e7ikolatadan yana m\u0131 kullansak acaba?<\/span><\/p>\n

Kaynak
\n<\/b>1) Johnson R.A. ve ark., \u201cCues play a critical role in estrous cycle-dependent enhancement of cocaine reinforcement\u201d, <\/span>Neuropsychopharmacology<\/span><\/i> 2019:1-9.
\n<\/span>2) Struik D., \u201cThe moldulating role of sex and anabolic-androgenic steroid hormones in canabinnoid sensitivity\u201d, <\/span>Front. Behav. Neurosci.<\/span><\/i>, 26 Ekim 2018.
\n<\/span>3)\u201cHigher estrogen levels linked to increased alcohol sensitivity in brain\u2019s reward center\u201d, University of Illinois at Chicago News, 6 Kas\u0131m 2017.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Kad\u0131nlar ve erkekler aras\u0131ndaki farklar herhalde g\u00fcndelik hayatta dilimize en s\u0131k dolad\u0131\u011f\u0131m\u0131z konulardan biridir. Oysa g\u00f6zlemledi\u011fimiz davran\u0131\u015f kal\u0131plar\u0131 ya yanl\u0131\u015f bir genellemeye kar\u015f\u0131l\u0131k gelir ya da b\u00fcy\u00fck \u00f6l\u00e7\u00fcde k\u00fclt\u00fcreldir, yani ba\u011flam\u0131na g\u00f6re de\u011fi\u015fir. Fakat bir fark var ki bu sohbetlere pek konu olmad\u0131\u011f\u0131 halde, ki\u015fisel kanaatlerle de\u011fil bilimsel deneylerle sabitlenecek kadar ger\u00e7ek: Kad\u0131nlar\u0131n alkol ve […]<\/p>\n","protected":false},"author":184,"featured_media":32621,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19,21,36],"tags":[4576,2359,4575,4577,4574],"class_list":["post-32625","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","category-biyoloji","category-psikoloji","tag-alkolizm","tag-esrar","tag-kokain","tag-ostrojen","tag-uyusturucu-bagimliligi"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t