- Title
- The effects of α-lactalbumin supplementation and handgrip contraction on soleus motoneuron excitability
- Creator
- Mackay-Phillips, Karen; Orssatto, Lucas; Polman, Remco; Van der Pols, Jolieke; Trajano, Gabriel
- Date
- 2023
- Type
- Text; Journal article
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/194448
- Identifier
- vital:18359
- Identifier
-
https://doi.org/10.1007/s00421-022-05101-3
- Identifier
- ISSN:1439-6319 (ISSN)
- Abstract
- Introduction: We tested two strategies that hypothetically increase serotonin availability (; Introduction: We tested two strategies that hypothetically increase serotonin availability (α-lactalbumin consumption and a remote submaximal handgrip contraction) on estimates of persistent inward currents (PICs) amplitude of soleus muscle in healthy participants. Methods: With a randomised, double-blind, and cross-over design, 13 healthy participants performed triangular-shaped ramp contractions with their plantar flexors (20% of maximal torque), followed by a 30-s handgrip sustained contraction (40% of maximal force) and consecutive repeated triangular-shaped contractions. This was performed before and after the consumption of either 40 g of α-lactalbumin, an isonitrogenous beverage (Zein) or an isocaloric beverage (Corn-starch). Soleus motor units discharge rates were analysed from high-density surface electromyography signals. PICs were estimated by calculating the delta frequency (ΔF) of motor unit train spikes using the paired motor unit technique. Results: ΔF (0.19 pps; p = 0.001; d = 0.30) and peak discharge rate (0.20 pps; p < 0.001; d = 0.37) increased after the handgrip contraction, irrespective of the consumed supplement. No effects of α-lactalbumin were observed. Conclusions: Our results indicate that 40 g of α-lactalbumin was unable to modify intrinsic motoneuron excitability. However, performing a submaximal handgrip contraction before the plantar flexion triangular contraction was capable of increasing ΔF and discharge rates on soleus motor units. These findings highlight the diffused effects of serotonergic input, its effects on motoneuron discharge behaviour, and suggest a cross-effector effect within human motoneurons. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. Erratum: Correction to: The effects of α‑lactalbumin supplementation and handgrip contraction on soleus motoneuron excitability - The original version of this article unfortunately contained a mistake. The corrected details are given below for your reading. The author’s name Karen Mackay-Phillips was incorrectly written as Karen Mackay Phillips. In section “Overview”, first sentence should read as “The current study was part of an experiment that has been divided in two parts, where some variables are presented in a companion paper (https:// doi. org/ 10. 1007/ s00421- 022- 05103-1).”. © 2022 Springer-Verlag GmbH Germany, part of Springer Nature.
- Publisher
- Springer Science and Business Media Deutschland GmbH
- Relation
- European Journal of Applied Physiology Vol. 123, no. 2 (2023), p. 395-404
- Rights
- All metadata describing materials held in, or linked to, the repository is freely available under a CC0 licence
- Rights
- Copyright © 2022, The Author(s)
- Rights
- Open Access
- Subject
- 3202 Clinical sciences; 3208 Medical physiology; 4207 Sports science and exercise; Motor neurone; Neuromodulation; Persistent inward currents; Serotonin; Tryptophan loading
- Full Text
- Reviewed
- Funder
- This work was funded by Queensland University of Technology as part of KM’s PhD candidature.
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