en Effect of finastride, an inhibitor of 5 α-reductase, on physical dependence induced by chronic administration of morphine in male rats Experimental research article Experimental research article <b><font face="TimesNewRomanPS-BoldMT" size="2"><p align="left">J Verdi and A Ahmadiani</p></font><i><font face="TimesNewRomanPS-BoldItalicMT" size="2"><p align="left">Dept. Pharmacology and Neuroscience Research Center, Shaheed Beheshti Univ. Med. Sci.,</p><p align="left">Tehran, Iran.</p></font><font face="TimesNewRomanPS-BoldMT" size="3"><p align="left">Abstract:</p></font><font face="TimesNewRomanPSMT" size="3"><p align="left">Tolerance and dependence are two main problems which have limited morphine administration as an analgesic</p><p align="left">drug. Following acute and chronic administration of morphine changes in the level of sex steroids and the activity</p><p align="left">of calcium channels are reported. The enzyme 5 α-reductase plays a pivotal role in the conversion of testosterone</p><p align="left">to dehydrotestosterone and therefore reduces the testosterone levels. In this investigation, we tried to study the</p><p align="left">effects of acute and chronic administration of finastride (inhibitor of 5 α-reductase) on morphine dependence in</p><p align="left">the male rats.</p><p align="left">Morphine dependency was induced by the intraperitoneal (i.p.) injection of morphine for 4 days (20, 30, 40 and</p><p align="left">40 mg/kg respectively at days 1-4). Physical dependence to morphine was observed following administration of</p><p align="left">naloxone (2 mg/kg-i.p., day 5).</p><p align="left">Acute administration of finastride at 5th day (5 mg/kg-i.p., twice with 2 hours interval), decreased all</p><p align="left">withdrawal signs significantly, while the administration the vehicle, caster oil, did not. Chronic administration</p><p align="left">of finastride prior to daily administration of morphine during days 1-4 significantly decreased all withdrawal</p><p align="left">signs at the day 5. This finding indicates that inhibition of testosterone metabolism in the CNS using</p><p align="left">finastride may be able to modulate the withdrawal sings expression and prevents the development of physical</p><p align="left">dependence.</p></font><b><font face="TimesNewRomanPS-BoldMT" size="3"><p align="left">Keywords: </p></font><font face="TimesNewRomanPSMT" size="3">5 alpha-reductase, Finastride, Dependence, Morphine</font></b></i></b> 159 162 http://ppj.phypha.ir/browse.php?a_code=A-10-71-1&slc_lang=en&sid=1