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Dopamine and Muscle Function in the Heat

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ClinicalTrials.gov Identifier: NCT03515668
Recruitment Status : Recruiting
First Posted : May 3, 2018
Last Update Posted : May 3, 2018
Sponsor:
Information provided by (Responsible Party):
Stephen Cheung, Brock University

Brief Summary:
our goal is to study the effects of dopamine activity, using Ritalin ingestion, on neuromuscular function over the course of a progressive heating and cooling protocol developed in our lab. We hypothesize that Ritalin will minimize the previously reported progressive impairment in neuromuscular function with hyperthermia compared to placebo, suggesting that dopamine activity preserves neuromuscular capacity with hyperthermia.

Condition or disease Intervention/treatment Phase
Muscle Force Hyperthermia Drug: Ritalin 20Mg Tablet Drug: Placebo Oral Tablet Not Applicable

Detailed Description:

Increased core temperature (hyperthermia) has been associated with impaired neuromuscular performance, with the majority of research suggesting that the observed fatigue is related to the central nervous system. Small doses of Ritalin has been used to study how changes in dopamine activity affects exercise capacity in the heat. This study found that 20 mg of Ritalin had no effect on exercise capacity in a thermoneutral environment of 18°C. However, when in a hot (30°C) environment, the Ritalin resulted in a 16% improvement in finishing time compared to the placebo trial. Interestingly, the higher output during the Ritalin-hot condition also resulted in higher rates of heat production and a higher (~0.6°C) core temperature, suggesting that dopamine enabled greater voluntary tolerance of hyperthermia. This matches recent work from our own work showing that motivational skills training increased both exercise tolerance and final core temperature, and it is possible that dopamine activity played a role in this improvement.

Ultimately, fatigue is shown in an inability to sustain muscular force. However, the role of dopamine activity on neuromuscular function (e.g., central activation and recruitment of muscle) during hyperthermia is unknown. One study reported that 20 mg of Ritalin did not alter neuromuscular function, but this study was done without thermal stress.

Therefore, our goal is to study the effects of dopamine activity, using Ritalin ingestion, on neuromuscular function over the course of a progressive heating and cooling protocol developed in our lab. We hypothesize that Ritalin will minimize the previously reported progressive impairment in neuromuscular function with hyperthermia (5, 7) compared to placebo, suggesting that dopamine activity preserves neuromuscular capacity with hyperthermia.


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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 14 participants
Allocation: Randomized
Intervention Model: Single Group Assignment
Intervention Model Description: Healthy males 18-30 years of age
Masking: Single (Investigator)
Masking Description: Double-blinding of participant and investigator, with independent investigator in charge of placebo and drug.
Primary Purpose: Basic Science
Official Title: The Influence of Dopamine Activity on Neuromuscular Function During Passive Heat Stress
Actual Study Start Date : April 20, 2018
Estimated Primary Completion Date : December 31, 2019
Estimated Study Completion Date : December 31, 2019

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Experimental: Ritalin
20 mg Ritalin, 90 min before testing
Drug: Ritalin 20Mg Tablet
Single dose for all participants

Placebo Comparator: Control
Identical size/taste placebo pill, 90 min before testing
Drug: Placebo Oral Tablet
Placebo with same appearance/taste




Primary Outcome Measures :
  1. Wrist flexion torque [ Time Frame: 2-4 hours after ingestion ]
    Maximal voluntary contraction of wrist flexion



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Ages Eligible for Study:   18 Years to 30 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • High aerobic fitness (>55 mL/kg/min maximal aerobic capacity)

Exclusion Criteria:

  • diagnosed cardiovascular, respiratory and/or neuromuscular disease, prescription of Ritalin or any drugs for hyperactivity within the past 1 year, any current prescription medication (except for asthma/allergy inhalers), any contraindications to Ritalin.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03515668


Contacts
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Contact: Stephen S Cheung, PhD 9056885550 ext 5662 scheung@brocku.ca

Locations
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Canada, Ontario
Brock University Recruiting
St Catharines, Ontario, Canada, L2S 3A1
Contact: Stephen Cheung, PhD    905 688-5550 ext 5662    scheung@brocku.ca   
Sponsors and Collaborators
Brock University

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Responsible Party: Stephen Cheung, Professor, Brock University
ClinicalTrials.gov Identifier: NCT03515668     History of Changes
Other Study ID Numbers: 17-123
First Posted: May 3, 2018    Key Record Dates
Last Update Posted: May 3, 2018
Last Verified: April 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Plan Description: No sharing planned

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
Additional relevant MeSH terms:
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Fever
Body Temperature Changes
Signs and Symptoms
Dopamine
Methylphenidate
Cardiotonic Agents
Sympathomimetics
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Dopamine Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Protective Agents
Central Nervous System Stimulants
Dopamine Uptake Inhibitors
Neurotransmitter Uptake Inhibitors
Membrane Transport Modulators