Facilitation of Extinction Retention and Reconsolidation Blockade by IV Allopregnanolone in PTSD

Summary

Purpose: About 6.4% of the U.S. population suffers from posttraumatic stress disorder (PTSD). Trauma-focused psychotherapies are generally effective in PTSD, but responses vary greatly across individuals and PTSD subpopulations. Neurobiological factors impacted by life experiences, stress, and genetics can affect treatment responses. These factors can alter brain capacities needed to reprocess traumatic memories prevent them from triggering intensely distressing, disruptive, out-of-place responses. For example, during psychotherapy for PTSD, trauma memory activation engages two competing brain processes that affect recovery: "extinction" versus "reconsolidation" of trauma-related emotional, physiological, and behavioral responses. This study tests whether a single intravenous (IV) dose of allopregnanolone (Allo) compared to placebo (which is non-active): 1. promotes consolidation of extinction learning (sub-study 1) or 2. blocks reconsolidation physiological responses triggered by aversive memories (sub-study 2). The study also tests whether Allo compared to placebo affects retention of non-aversive memories.

Description

Eligibility

Age range

18–55 years

Sex

All

Healthy volunteers

No

Interventions

• Behavioral
  3-day differential fear conditioning, extinction, and extinction retention testing paradigm

  Day 1: Fear acquisition involving the pairing of a brief, noxious but not painful air blast to the neck (unconditioned stimulus; US) to a conditioned stimuli (CS) (Expts. 1 and 2). The CS will be different colored shapes appearing on a computer monitor. An auditory stimulus will serve as the startle probe. Day 2: Either extinction training (Expt. 1) or fear memory reactivation by a single CS+ with no US (Expt. 2) will occur followed by IV Allo vs. IV placebo administration. Day 3: The effects of IV Allo vs. IV placebo (administered on Day 2) on extinction retention (Expt. 1) or reconsolidation blockade (Expt. 2), as well as reinstatement of conditioned fear (Expts. 1 and 2) will be assessed.

• Drug
  Allopregnanolone (Allo) with Dexolve in 0.9% saline for injection manufactured by University of California, Davis

  Expt. 1 (extinction retention): On Day 2, a 1.7 ug/kg IV bolus of Allo will be administered over 5 minutes at the completion of extinction training and continued as a 5-hour drip to maintain resting plasma Allo levels at \~1500 pg/ml. Expt. 2 (reconsolidation blockade): On Day 2, a 28 ug/kg IV bolus of Allo will be infused over 30 minutes immediately following presentation of a single CS+.

• Other
  Matching IV Placebo

  Expt. 1 (extinction retention): On Day 2, a 1.7 ug/kg IV bolus of the matching placebo formulation will be administered over 5 minutes at the completion of extinction training and continued as a 5-hour drip to maintain resting plasma Allo levels at \~1500 pg/ml. Expt. 2 (reconsolidation blockade): On Day 2, a 28 ug/kg IV bolus of the matching placebo formulation will be infused over 30 minutes immediately following presentation of a single CS+.

Locations (2)