Acute Pain, Chronic Pain, Widespread, Schizophrenia
Conditions
Keywords
Ketamine, ERP, Oddball
Brief summary
This is a clinical trial that intend to determine the effects of S-ketamine on event-related potentials associated with semantic affective pain-processing
Detailed description
Ketamine is a unique anesthetic with neural effects that are distinct from more commonly-used γ-aminobutyric acid agonists. Evidence suggest that analgesic effect of ketamine is primarily related to the affective than the sensorial aspects of pain interpretation. The investigators investigated whether ketamine, a noncompetitive NMDA antagonist, would modify the perceived emotional valence of pain-related words when compared to non-pain-related ones in healthy volunteers. Using a single session double-blind parallel placebo-controlled design, 24 healthy volunteers were randomized to receive intravenous S-ketamine (n=12) or placebo (n=12). During infusion (plasmatic target of 60 ng/ml), the effects of ketamine were recorded using EEG and oddball behavioral data was monitored. Evoked potentials (N200 and P300 components) were recorded during performance of a semantic written word oddball task containing pain-related (targets) and non-pain-related words (standards). Expected results: The findings of this study can help in the understanding of neurophysiologic mechanisms involved in ketamine's effects both in psychiatric diseases as in the treatment of postoperative acute and chronic pain.
Interventions
DRUGKetamine
S-ketamine will be administered in precalculated infusion rates to obtain a plasmatic level of 60 ng/ml
DRUGPlacebo
Administered in an identical way than ketamine.
Sponsors
Hospital de Clinicas de Porto Alegre
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* male healthy subjects with higher education level
Exclusion criteria
* do not understand Portuguese language * obese patients (BMI \> 27 kg/m2) * use of NSAID, steroids, analgesics, anticonvulsant drugs, as well as alpha and beta-blockers * score ≥ 13 on Beck II Questionnaire * sleep deprivation in the night before evaluation
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| AUC of the grand averaged mean differences between ERPs elicited by target and non-target words | up to 60 min | EEG will be recorded during all task time. The main outcome will be the area under de curve (AUC) of the grand averaged mean differences between event-related potencials (ERPs) elicited by target and non-target words at 100-200, 300-500 and 800-900 ms after stimulus presentation for parietal electrophysiological signal (Pz). The ERPs represent the averaged voltage of several trials. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Word ratings related to the semantic valence | up to 60 min | After viewing each word, volunteers were asked to classify them according to the semantic valence in the following categories: positive, negative or neutral. |
| Response times (behavioural oddball data) | up to 60 min | Response times to word classification in oddball task |
Other
| Measure | Time frame | Description |
|---|---|---|
| Subjective euphoria rating | up to 60 min | Euphoria will be rated using an analogue visual scale ranging of 0 to 10. |
| Subjective sedation rating | up to 60 min | Sedation will be rated using an analogue visual scale ranging of 0 (completely awake) to 100 (sleeping). |
Outcome results
None listed