Autonomic FunctionCPB_AtropineNCT06912048
Understanding Individual Variability in Neuronal Signal Transmission to Target Organs in Health and Disease
A study testing Oral glucose tolerance test with double-tracer dilution and atropine infusion in people with Autonomic Function, run by University of Ulm at 1 site in Germany.
Trial summary
The goal of this clinical trial is to evaluate the influence of parasympathetic transmission from the brain to different metabolic organs. This transmission can be blocked with the muscarinic antagonist atropine. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Autonomic Function
- What is being tested?
- Oral glucose tolerance test with double-tracer dilution and atropine infusion
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 52 participants
- Where
- 1 siteGermany
- Study dates
- 14 May 2025to May 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age: at least 18
- BMI: 20 - 24.9 kg/m2 (for the healthy groups) or more than 28 kg/m2 (for the overweight groups)
- For women: Hormonal contraception with a single-phase preparation (e.g. Nuvaring)
- Understanding and voluntarily signing an informed consent form prior to study-related examinations
Who cannot join
- Drug and/or alcohol abuse
- smoking
- Taking medication that affects blood sugar or addresses the central and/or autonomic nervous system (e.g. anti-epileptic drugs, beta blockers, dopamine agonists, antidepressants). Taking antihistamines.
- Pre-existing cardiac conditions
- Neurological pre-existing conditions
- Known cardiac arrhythmia
Show all 17Show fewer
- Known allergies to ingredients, e.g. paracetamol and atropine
- Known narrow-angle glaucoma
- Known hyperthyroidism
- Known diseases of the urinary tract or prostate
- Pregnancy or breastfeeding
- At screening: Hb < 12 g/dl for women and Hb < 14 g/dl for men
- No consent to be informed about incidentally discovered pathological findings
- Any (clinical) condition which, in the opinion of the physician, could jeopardize the safety of the
- or would jeopardize the scientific success.
- Liver dysfunction
- Renal insufficiency
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Andrea Geissler contact
Germany1 site, 1 recruiting
- Recruiting
Ulm University Hospital
Ulm, 89081
Sabrina Wangler, +4973150044782, sabrina.wangler@uniklinik-ulm.de
Andrea Geissler, andrea.geissler@uniklinik-ulm.de
About this study
The goal of this clinical trial is to evaluate the influence of parasympathetic transmission from the brain to different metabolic organs. This transmission can be blocked with the muscarinic antagonist atropine.
Participants will undergo an oral glucose tolerance test combined with a double tracer dilution technique either with atropine infusion or placebo.
Healthy individuals and high-risk individuals will be compared to identify possible changes in signaling in high-risk groups. In addition, men and women will be included to take into account possible sex differences.
Read the detailed description
This research project aims to investigate to what extent the parasympathetic nervous system is responsible for the transmission of signals from the brain to peripheral organs. Furthermore, the study will investigate sex differences and differences between healthy and high-risk individuals on brain-derived coordination of postprandial signaling for metabolic control.
Therefore, parasympathetic blockade will be introduced by atropine infusion (on one day) versus saline infusion as placebo (on another day) in a randomized fashion. For safety reasons, only the participants will be blinded. Infusion will start 20 minutes before a 75 gram oral glucose tolerance test (oGTT) and last until the end of the 2h oGTT. The oGTT will introduce a postprandial state. Additionally, 1000 mg Paracetamol will be added to the solution to study gastric emptying.
This approach will be combined with a double-tracer dilution technique. Labeled glucose ([6,6-2H]glucose) will be infused 120 minutes before and during the oGTT (120 min) and will be used to address endogenous glucose production. The glucose drink from the oGTT will be enriched with [U-13C6]glucose to compute the glucose appearance rate (Ra). Basal endogenous glucose production will be calculated as well as post-load endogenous glucose production and rates of glucose disappearances (Rd).
- Conditions
- Autonomic Function
- Being tested
- Oral glucose tolerance test with double-tracer dilution and atropine infusion, Oral glucose tolerance test with double-tracer dilution and saline infusion (placebo)
- Keywords
- parasympathetic transmission, autonomic nervous system, brain periphery crosstalk, metabolism, insulin sensitivity, insulin secretion, endogenous glucose production, sex differences, high risk population
- Medical subject headings
- Insulin Resistance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Oral glucose tolerance test with double-tracer dilution and atropine infusionOther
Subjects will undergo a 75 g oGTT (180 min) combined with a double tracer dilution. The double-tracer dilution technique will be used to quantify endogenous glucose production, glucose appearance and disappearance rate. [6,6-2H]glucose will be infused for a total of 300 minutes, while the infusion will start 120 minutes prior the oGTT and will last until the end of the oGTT. Atropine infusion will be administered 20 minutes before the start of the oGTT. The drink consumed at time point 0 min contains 75 gram glucose, enriched with [U-13C6]-glucose.
Oral glucose tolerance test with double-tracer dilution and saline infusion (placebo)Other
Subjects will undergo a 75 g oGTT (180 min) combined with a double tracer dilution. The double-tracer dilution technique will be used to quantify endogenous glucose production, glucose appearance and disappearance rate. [6,6-2H]glucose will be infused for a total of 300 minutes, while the infusion will start 120 minutes prior the oGTT and will last until the end of the oGTT. Saline infusion will be administered 20 minutes before the start of the oGTT. The drink consumed at time point 0 min contains 75 gram glucose, enriched with [U-13C6]-glucose.
| Study group | Role | What they receive |
|---|---|---|
| Atropine Infusion | Experimental | 5 µg x kg fat free mass-1 x h-1 Receives: Other: Oral glucose tolerance test with double-tracer dilution and atropine infusion |
| Saline infusion | Placebo comparator | Not described Receives: Other: Oral glucose tolerance test with double-tracer dilution and saline infusion (placebo) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Glucose tolerance
Effect of parasympathetic blockade with atropine versus placebo on glucose tolerance assessed as area under the glucose curve (0-120 minutes) and glucose levels at timepoint 120 minutes during the 75 g oral glucose tolerance test.
Measured: 120 minutes
Insulin Sensitivity
Effect of parasympathetic blockade with atropine versus placebo on insulin sensitivity assessed from glucose and insulin measurements during the 75 g oral glucose tolerance test.
Measured: 120 minutes
Insulin Secretion
Effect of parasympathetic blockade with atropine versus placebo on insulin secretion assessed from glucose and insulin/C-peptide measurements during the 75 g oral glucose tolerance test.
Measured: 180 minutes
Secondary outcomes (9)
Lipolysis
Effect of parasympathetic blockade with atropine versus placebo on the suppression of lipolysis during a 75 g oral glucose tolerance test.
Measured: 120 minutes
Gastric emptying
Effect of parasympathetic blockade with atropine versus placebo on gastric emptying during the 75 g oral glucose tolerance test.
Measured: 120 minutes
Amino Acid Metabolism
Effect of parasympathetic blockade with atropine versus placebo on amino acid metabolism assessed by amino acid measurements during the 75 g oral glucose tolerance test.
Measured: 120 minutes
Bile acid metabolism
Effect of parasympathetic blockade with atropine versus placebo on bile acid metabolism assessed by bile acid measurements during the 75 g oral glucose tolerance test.
Measured: 120 minutes
Substrate oxidation
Effect of parasympathetic blockade with atropine versus placebo on substrate oxidation assessed by indirect calorimetry at timepoints -110 Minutes, 30 Minutes, 60 Minutes and 120 Minutes during the 75 g oral glucose tolerance test.
Measured: 230 Minutes
Incretin secretion
Effect of parasympathetic blockade with atropine versus placebo on incretin secretion during the 75 g oral glucose tolerance test.
Measured: 120 minutes
Sex differences
Explore sex differences in the effect of parasympathetic blockade with atropine versus placebo in the mentioned outcome measures.
Measured: 180 minutes
Autonomic nervous system
Effect of parasympathetic blockade with atropine versus placebo on the autonomic nervous system assessed by heart rate variability during the 75 g oral glucose tolerance test.
Measured: 180 minutes
Blood coagulation parameters
Influence of of parasympathetic blockade with atropine versus placebo on blood coagulation parameters. This is assessed through global coagulation tests and single coagulation factors.
Measured: 120 Minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Apr 2025
- Study start14 May 2025
- Primary completionApr 2027 (estimated)
- Study completionMay 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Autonomic FunctionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 52 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Ulm
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Martin Heni, University of Ulm
- Investigators
- Martin Heni, MD, Principal investigator, Ulm University Hopital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06912048
- Sponsor's protocol ID
- 467/2024
- Other IDs
- 101125605
- Acronym
- CPB_Atropine
- Status last verified
- Mar 2025
- First submitted
- 28 Mar 2025
- Last updated
- 10 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Understanding Individual Variability in Neuronal Signal Transmission to Target Organs in Health and Disease
- ClinicalTrials.gov ID
- NCT06912048
- Acronym / sponsor ID
- CPB_Atropine / 467/2024
- Conditions
- Autonomic Function
- Keywords
- parasympathetic transmission, autonomic nervous system, brain periphery crosstalk, metabolism, insulin sensitivity, insulin secretion, endogenous glucose production, sex differences
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 52 participants (estimated)
- Lead sponsor
- University of UlmUniversity, hospital or other
- Study start
- 14 May 2025 (actual)
- Primary completion
- Apr 2027 (estimated)
- Study completion
- May 2027 (estimated)
- First posted
- 4 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to evaluate the influence of parasympathetic transmission from the brain to different metabolic organs. This transmission can be blocked with the muscarinic antagonist atropine.
Participants will undergo an oral glucose tolerance test combined with a double tracer dilution technique either with atropine infusion or placebo.
Healthy individuals and high-risk individuals will be compared to identify possible changes in signaling in high-risk groups. In addition, men and women will be included to take into account possible sex differences.
Detailed description
This research project aims to investigate to what extent the parasympathetic nervous system is responsible for the transmission of signals from the brain to peripheral organs. Furthermore, the study will investigate sex differences and differences between healthy and high-risk individuals on brain-derived coordination of postprandial signaling for metabolic control.
Therefore, parasympathetic blockade will be introduced by atropine infusion (on one day) versus saline infusion as placebo (on another day) in a randomized fashion. For safety reasons, only the participants will be blinded. Infusion will start 20 minutes before a 75 gram oral glucose tolerance test (oGTT) and last until the end of the 2h oGTT. The oGTT will introduce a postprandial state. Additionally, 1000 mg Paracetamol will be added to the solution to study gastric emptying.
This approach will be combined with a double-tracer dilution technique. Labeled glucose ([6,6-2H]glucose) will be infused 120 minutes before and during the oGTT (120 min) and will be used to address endogenous glucose production. The glucose drink from the oGTT will be enriched with [U-13C6]glucose to compute the glucose appearance rate (Ra). Basal endogenous glucose production will be calculated as well as post-load endogenous glucose production and rates of glucose disappearances (Rd).
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Atropine Infusion | Experimental | Other: Oral glucose tolerance test with double-tracer dilution and atropine infusion5 µg x kg fat free mass-1 x h-1 |
| Saline infusion | Placebo comparator | Other: Oral glucose tolerance test with double-tracer dilution and saline infusion (placebo) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Age: at least 18
- BMI: 20 - 24.9 kg/m2 (for the healthy groups) or more than 28 kg/m2 (for the overweight groups)
- For women: Hormonal contraception with a single-phase preparation (e.g. Nuvaring)
- Understanding and voluntarily signing an informed consent form prior to study-related examinations
Key exclusion criteria (17 listed)
- Drug and/or alcohol abuse
- smoking
- Taking medication that affects blood sugar or addresses the central and/or autonomic nervous system (e.g. anti-epileptic drugs, beta blockers, dopamine agonists, antidepressants). Taking antihistamines.
- Pre-existing cardiac conditions
- Neurological pre-existing conditions
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Oral glucose tolerance test with double-tracer dilution and atropine infusionSubjects will undergo a 75 g oGTT (180 min) combined with a double tracer dilution. The double-tracer dilution technique will be used to quantify endogenous glucose production, glucose appearance and disappearance rate. [6,6-2H]glucose will be infused for a total of 300 minutes, while the infusion will start 120 minutes prior the oGTT and will last until the end of the oGTT. Atropine infusion will be administered 20 minutes before the start of the oGTT. The drink consumed at time point 0 min contains 75 gram glucose, enriched with [U-13C6]-glucose. | Other | Atropine Infusion |
| Oral glucose tolerance test with double-tracer dilution and saline infusion (placebo)Subjects will undergo a 75 g oGTT (180 min) combined with a double tracer dilution. The double-tracer dilution technique will be used to quantify endogenous glucose production, glucose appearance and disappearance rate. [6,6-2H]glucose will be infused for a total of 300 minutes, while the infusion will start 120 minutes prior the oGTT and will last until the end of the oGTT. Saline infusion will be administered 20 minutes before the start of the oGTT. The drink consumed at time point 0 min contains 75 gram glucose, enriched with [U-13C6]-glucose. | Other | Saline infusion |
Primary outcome
Glucose tolerance
Time frame: 120 minutes
Effect of parasympathetic blockade with atropine versus placebo on glucose tolerance assessed as area under the glucose curve (0-120 minutes) and glucose levels at timepoint 120 minutes during the 75 g oral glucose tolerance test.
Insulin Sensitivity
Time frame: 120 minutes
Effect of parasympathetic blockade with atropine versus placebo on insulin sensitivity assessed from glucose and insulin measurements during the 75 g oral glucose tolerance test.
Insulin Secretion
Time frame: 180 minutes
Effect of parasympathetic blockade with atropine versus placebo on insulin secretion assessed from glucose and insulin/C-peptide measurements during the 75 g oral glucose tolerance test.
9 secondary outcomes
Lipolysis
Time frame: 120 minutes
Gastric emptying
Time frame: 120 minutes
Amino Acid Metabolism
Time frame: 120 minutes
Bile acid metabolism
Time frame: 120 minutes
Substrate oxidation
Time frame: 230 Minutes
Incretin secretion
Time frame: 120 minutes
Sex differences
Time frame: 180 minutes
Autonomic nervous system
Time frame: 180 minutes
Blood coagulation parameters
Time frame: 120 Minutes
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Jul 2025.
- Individual participant dataSharing planned: No
Related trials for Autonomic Function
Not yet recruiting
Physiology of Liberation
Psychophysiological Reactivity and Recovery
Recruiting
Impact of Pre- and Early Post-operative Isometric Handgrip Training on Functional Capacity and Autonomic Function After Sternotomy
Sternotomy, Functional Capacity
Not yet recruitingObservational study
Early Heart Rate Variability and Sleep and Quality of Recovery After Cesarean Delivery
Recovery of Function, Postoperative Period
RecruitingObservational study
Rare Disease Patient Registry & Natural History Study - Coordination of Rare Diseases at Sanford
Rare Disorders, Undiagnosed Disorders
Enrolling by invitationObservational study
Heart Rate Variability and Medication Adherence in Resistant Hypertension
Resistant Hypertension, Medication Adherence
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Andrea Geissler contact
Martin Heni, MD principal investigator
Ulm University Hopital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Oral glucose tolerance test with double-tracer dilution and atropine infusion in people with Autonomic Function, run by University of Ulm at 1 site in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 10 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Martin Heni, MD (+4973150044505, martin.heni@uniklinik-ulm.de), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Glucose tolerance (time frame: 120 minutes). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jul 2025.