Brain Responses to Intragastric Administration of a Bitter Agonist in Homeostatic and Hedonic Brain Regions

Study Overview
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Brief Summary
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The investigators aim to study the brain mechanisms underlying the effect of subliminal (not consciously perceived) intragastric administration of bitter tastants on hunger and food intake, which was previously found. The investigators will assess brain activation patterns after an acute intragastric administration of Quinine-hydrochloride versus saline on two different test days, and will simultaneously assess a putative role of altered gut peptide release in these effects. The hypothesis is that intragastric infusion of a bitter agonist will decrease the activity in homeostatic and hedonic brain regions and that this effect is mediated by gut peptide release.

Official Title
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Brain Responses to Intragastric Administration of a Bitter Agonist in Homeostatic and Hedonic Brain Regions

Conditions
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Healthy

Intervention / Treatment
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* Other: Quinine hydrochloride
* Other: Control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy volunteers Female N = 15 Age 18 - 60 Body Mass Index (BMI) of 20 - 25 kg/m Stable body weight for at least 3 months prior to the start of the study Exclusion Criteria: Abdominal or thoracic surgery. Exception: appendectomy Gastrointestinal, endocrine or neurological diseases Cardiovascular, respiratory, renal or urinary diseases Hypertension Food or drug allergies Anemia Eating disorders and people who show abnormal eating behavior Depressive disorders Psychotic disorders No medication on a regular basis, expect for oral contraception Conditions that can interfere with functional magnetic resonance imaging (fMRI), e.g. cochlear implants, metal fragments or metal implants in the body, pacemaker, neural stimulator, … No history of cannabis use or any other drug of abuse for at least 12 months prior to the study Alcohol abuse (more than 21 units of alcohol for men, more than 14 units for woman per week) Dieters Pregnant or breastfeeding women Claustrophobia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control<br>Intragastric infusion | Other: Control<br>* Intragastric administration of distilled water<br>|
| Experimental: Quinine hydrochloride<br>Intragastric infusion | Other: Quinine hydrochloride<br>* Intragastric administration of a bitter tastant agonist (10 μmol/kg quinine-hydrochloride)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional brain images | Change in brain responses after administration compared to baseline will be assessed via functional magnetic resonance imaging. | From the start of the study until 50 minutes after the start of the study | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| hunger scores | The hunger scores will be taken every 10 minutes since the scan starts via a 10 cm visual analogue scale. | every 10 minutes since the scan starts until until 50 minutes after the start of the scan | 
| Ghrelin levels | Peripheral blood samples will be taken every 10 min since the scan starts until the endpoint of the study to measure ghrelin levels by radioimmuno-assay. | every 10 min since the scan starts until 50 minutes after the start of the scan. | 
| Motilin levels | Peripheral blood samples will be taken every 10 min since the scan starts until the endpoint of the study to measure motilin levels by radioimmuno-assay. | every 10 min since the scan starts until 50 minutes after the start of the scan | 
| CCK levels | Peripheral blood samples will be taken every 10 min since the scan starts until the endpoint of the study to measure CCK levels by radioimmuno-assay. | every 10 min since the scan starts until 50 minutes after the start of the scan | 
| PYY levels | Peripheral blood samples will be taken every 10 min since the scan starts until the endpoint of the study to measure PYY levels by Enzyme-Linked Immuno Sorbent Assay | every 10 min since the scan starts until 50 minutes after the start of the scan | 
| GLP-1 levels | Peripheral blood samples will be taken every 10 min since the scan starts until the endpoint of the study to measure GLP-1 levels by Enzyme-Linked Immuno Sorbent Assay | every 10 min since the scan starts until 50 minutes after the start of the scan |