Emotions
Conditions
Brief summary
This study is firstly designed to investigate acute and delayed effects of a single dose of ketamine on functional brain changes during emotional and cognitive challenges and at rest. Secondly, it aims to investigate whether functional brain changes after ketamine require increased glutamatergic signaling and will accordingly be modulated after pretreatment with lamotrigine.
Detailed description
Despite the rapid antidepressant effects of ketamine, its increasing use as an AD and the recent (2019) FDA approval of ketamine nasal spray as medication for treatment-resistant depression, the exact neurobiological mechanisms underlying its effects remain unclear. There are numerous reasons, why so far there has been no coherent explanatory framework. Most previous studies focused on investigating a single domain such as functional connectivity (e.g. Deakin et al., 2008; Scheidegger et al., 2012), functional brain changes to either cognitive (e.g. Honey et al., 2005; Driessen et al., 2013) or emotional challenge (e.g. Scheidegger & Grimm et al., 2016; Reed et al., 2019), perfusion (e.g. Pollack et al., 2015), magnetic fields (Salvadore et al., 2010) or neurotransmitter concentrations (e.g. Abdallah et al., 2018). Small sample sizes of as little as 8 subjects, the lack of a control group, the limited number of timepoints for measurement of the above-mentioned parameters, and the failure to modulate glutamatergic signalling after ketamine further limit the informative value of previous findings. What is therefore urgently needed in order to better understand the mechanisms of ketamine, is a study that combines neuroimaging in several modalities, investigates acute as well as delayed effects of ketamine and applies an approach to modulate glutamatergic signaling after ketamine. Accordingly, this study is designed to investigate acute and delayed effects of a single dose of ketamine on functional brain changes during emotional and cognitive challenge and at rest as well as to investigate the functional significance of increased glutamatergic signalling after ketamine. Measurement of functional brain changes will occur during (acute) and 24 hrs. after a single dose of ketamine, as differential effects are hypothesized. To modulate glutamatergic signaling after ketamine, a lamotrigine pretreatment protocol will be used. It is hypothesized that functional brain changes previously linked to ketamine require increased glutamatergic signaling and will be attenuated by pretreatment with lamotrigine. To test these hypotheses, we will implement a randomized, placebo-controlled, parallel-group design with 3 treatment conditions (lamotrigine + ketamine, placebo + ketamine, placebo + placebo). All subjects will undergo two scanning sessions (acute + post 24 hrs.). In order to include baseline values as covariates in the analyses, imaging will begin 10 minutes before infusion of ketamine/placebo. Pretreatment with lamotrigine or matching placebo will occur 2 hours before the ketamine/placebo infusion. Blood samples will be taken at 0:30, 1:00, 1:30, 2:55 and 4 hours following oral drug administration to determine the plasma pharmacokinetics of lamotrigine, and at 40 minutes after commencing ketamine infusion to confirm target ketamine plasma levels.
Interventions
DRUGLamotrigine
Orally; 300 mg
DRUGKetamine
Intravenously; 0.12 mg/kg during the first minute followed by a continuous infusion of approximately 0.31 mg/kg/h over approx. 40 min
DRUGPlacebo Pretreatment
Lamotrigine Placebo
DRUGPlacebo Infusion
Ketamine Placebo
Sponsors
Boehringer Ingelheim
Charite University, Berlin, Germany
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
Main Inclusion Criteria: * From 18 to 45 years of age, inclusive * Body Mass Index (BMI) between 18.0 and 28.5 kg/m2, inclusive * Healthy on the basis of physical examination, medical history, vital signs, clinical laboratory tests, and 12-lead ECG Main
Exclusion criteria
* Clinically relevant allergy or drug hypersensitivity * A history of psychiatric or neurologic disorders * Alcohol or substance dependence within the last 12 months from screening * A positive urine drug screen at any visit * MR
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Functional brain changes induced by emotional and cognitive challenge | Measurements will occur during (acute) and 24h after (delayed) a single dose of ketamine | The primary endpoints of efficacy are the functional brain changes induced by emotional and cognitive challenge during ketamine infusion as compared to placebo and to the responses during ketamine infusion after Lamotrigine pretreatment during and after (post 24 hrs.) in following brain regions (bilateral): * Amygdala * Hippocampus * Dorsolateral Prefrontal Cortex * Anterior cingulate Cortex * Insula |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in cerebral blood flow in predefined brain regions | Measurements will occur during and 24h after a single dose of ketamine | Changes in cerebral blood flow (ASL) in in the following brain regions (bilateral): Amygdala, Hippocampus, Dorsolateral Prefrontal Cortex, Anterior cingulate Cortex and Insula. During ASL, subjects engage in no special task, but are asked to close their eyes and relax. ASL provides quantitative parametric images of tissue perfusion. |
| Association between functional brain changes during emotional and cognitive challenge and ketamine- induced dissociative state | Measurements will occur during and 24h after a single dose of ketamine | Dissociate state will be investiagted using the Dissoziations-Spannungs-Skala akut (DSS-akut, Stiglmayr et al. 2003). |
| Changes in resting- state functional connectivity in default- mode network (DMN) and affective network (AN) | Measurements will occur at baseline, during and 24h after a single dose of ketamine | Changes in resting- state functional connectivity in default- mode network (DMN) and affective network (AN) in the following brain regions (bilateral): Amygdala, Hippocampus, Dorsolateral Prefrontal Cortex, Anterior cingulate Cortex and Insula. During the resting state scan, During this scan, subjects are asked to relax and to keep their eyes open. |
| Blood concentration of lamotrigine | Measurements will occur at baseline as well as 0.30, 1:00, 1:30, 2:55 and 4h following drug administration | Blood samples are taken to determine citrate plasma concentration of Lamotrigine to assess plasma levels during fMRI assessments. |
| Blood concentration of ketamine | Measurements will occur approx. 40 minutes after commencing ketamine infusion | Blood samples are taken to determine citrate plasma concentration of Ketamine to confirm target exposures (plasma levels) during assessments. |
| Association between changes in resting- state functional connectivity and ketamine- induced dissociative state | Measurements will occur during and 24h after a single dose of ketamine | Dissociate state will be investiagted using the Dissoziations-Spannungs-Skala akut (DSS-akut, Stiglmayr et al. 2003). |
Countries
Germany
Outcome results
None listed