endogenousopioidsystemisinvolvedinacuteresponsetonicotineandthedevelopmentand maintenanceofnicotinedependence.Accordingly,onedrugbeinginvestigatedforsmokingcessation treatmentisnaltrexone,aopioidreceptorantagonist.However,recentclinicaltrialsexaminingtheefficacyof adjunctivetreatmentwithnaltrexoneinsmokingcessationhaveyieldedmixedresultsand,therefore,further researchisneeded.Ofpotentialrelevancetotheseclinicaloutcomes,boththeendogenousopioidsystemand nicotinehaveactiononthehypothalamicpituitaryadrenal(HPA)axis,asystemthatisprimarilyassociated withresponsetostress.SmokershaveanacutelyunderresponsiveHPAaxistostressorsor pharmacologicalactivationcomparedtononsmokers.Importantly,thisHPAaxisdysfunctionmayplayarole inmaintenanceofaddictionandsusceptibilitytorelapse.NaltrexoneacutelyactivatestheHPAaxisandithas beenpreviouslyhypothesizedthatthisincreaseinHPAaxisactivitymayunderlienaltrexone'sefficacyfor treatmentofalcoholismandpossiblysmoking.However,therelationshipbetweennaltrexone'sactiononthe HPAaxisanditsreductionofsmokingbehaviorhasnotbeeninvestigated.Finally,theremaybeimportant,yet unexploredsexdifferencesinsmokers'responsetonaltrexone.Womensmokershaveshownmoreacute sensitivitytonaltrexonethanmenintermsofsubjective,behavioral,andHPAaxishormonemeasures,aswell asbetterquitratesinsmokingcessationtrialsusingnaltrexone.Thesereportedsexdifferencesmaybe relatedtodifferencesinlevelsofestradiol,thepredominantestrogeninhumans,betweenmenandwomen.In women,fluctuationsinestradiollevelsacrossthemenstrualcyclemayaffecttheamountofavailableopioid receptorsand,therefore,mayaffecttheefficacyofnaltrexone.Thestudiesinthisapplicationaredesignedto testtheeffectsofnaltrexoneontheHPAaxisandsmokingbehaviorinmaleandfemalesmokers,andto examinehowestradiollevelaffectstheseresponsestonaltrexoneinfemalesmokers.Inordertoexaminethe effectofestradiolonresponsetonaltrexone,womenwillbetestedattwodifferentstagesofthemenstrual cycle:theearlyfollicularphase(thelowestlevelofestradioloccurringduringthemenstrualcycle)andthelate follicularphase(thehighestoccurringlevelofestradiol).Theresultsofthisstudywouldpotentiallyprovide evidenceforestradiollevelasamechanismunderlyingsexdifferencesinresponsetonaltrexoneandmay havetranslationalclinicalimplicationsfortheuseofnaltrexoneinsmokingcessation.

Public Health Relevance

The proposed study relates to public health in that it will investigate how men and women smokers may differ in response to a drug (naltrexone) that is being examined for use in smoking cessation. The results of this study may have direct implications in the manner that women (or men) are treated using naltrexone.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31DA030073-02
Application #
8365275
Study Section
Special Emphasis Panel (ZRG1-F11-L (20))
Program Officer
Gordon, Harold
Project Start
2011-09-30
Project End
2013-09-29
Budget Start
2012-09-30
Budget End
2013-09-29
Support Year
2
Fiscal Year
2012
Total Cost
$42,232
Indirect Cost
Name
University of Chicago
Department
Psychiatry
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637