Glutamate-Glutamine Cycling (VCYC) During Cocaine Abstinence Using 13C-MRS


Given prior evidence of reduced resting-state glucose uptake in prefrontal cortex (PFC) as measured by [18F]-FDG PET (Volkow 1992, 1993) and direct neurometabolic coupling of cortical glucose oxidation and glutamate transmission, we hypothesize that [13C]-MRS measures of VTCA and VCYC will be reduced in individuals abstinent from cocaine as compared to HCs. We will also explicitly explore potential relationships between VCYC and neurocognitive tests of PFC function and clinical outcomes (i.e., measures of relapse at 90-days outpatient follow-up). In addition to assessing resting-state glucose uptake in the PFC, we will explore whether open-label administration of either of three different pharmacological treatments (N-acetyl cysteine, riluzole, or pentoxifylline) increases VCYC, in cocaine users (CU) in comparison to their abstinence baseline.

Study Start Date

February 2014

Estimated Completion Date

January 2018


  • Drug: riluzole
  • Behavioral: Continued abstinence
  • Drug: pentoxifylline
  • Drug: N-acetyl cysteine
  • Drug: 13C MRS


  • Psychiatry : Substance Abuse
  • Pharmacy: Adverse Drug Reactions,Pain Management
  • Nurse Practitioner: Substance Abuse

MeSH Terms

  • Cocaine-Related Disorders
  • N-acetyl cysteine
  • riluzole

Study ID

Yale University -- 1311013082



Trial ID


Study Type


Trial Phase

Phase 1

Enrollment Quota



Yale University

Inclusion Criteria

    1. Age 21-50 years 2. Voluntary, written, informed consent 3. Physically healthy 4. DSM-IV criteria for Cocaine Abuse (305.60) or Cocaine Dependence (304.20) 5. Documented evidence (by urine toxicology) of abstinence from cocaine (2 weeks for scan 1 and 4 weeks for scan 2) 6. For females, a negative serum or urine pregnancy (?-HCG) test.

Exclusion Criteria

    1. A history of other substance dependence (e.g., alcohol, opiates, sedative hypnotics), except for nicotine 2. A primary DSM-IV Axis I major psychiatric disorder (e.g., schizophrenia, bipolar disorder, major depression, etc.) as determined by the Structured Clinical Interview for DSM-IV (SCID) 3. A history of significant medical (e.g., cardiovascular, diabetic/metabolic) or neurological (e.g., cerebrovascular, seizure, traumatic brain injury) illness 4. Current use of psychotropic and/or potentially psychoactive prescription medications 5. Medical contraindications to participation in a magnetic resonance imaging procedure (e.g., ferromagnetic implants/foreign bodies, claustrophobia, cardiac pacemaker, prosthetic valve, otologic implant, etc.) 6. For females, physical or laboratory (?-HCG) evidence of pregnancy 7. For subjects interested in pharmacotherapy component, history of allergies to NAC, RIL, or PTX and current elevation on liver function tests above twice the normal limit.




18 Years to 50 Years

Accepts Healthy Volunteers

Accepts Healthy Volunteers

Study Locations and Contact Information (1)

Study Location Distance Name Phone Email
Connecticut Mental Health Center - New Haven, Connecticut 17.3 miles None None None provides clinical trial listings in an easy to view format. All clinical trial information is pulled directly from This website does not guarantee acceptance into any clinical trial, and is not responsible for adverse events that may be incurred from a clinical trial.