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Popov A, Lyakhovetskii V, Gorskii O, Kalinina D, Pavlova N, Musienko P. Effect of Hindlimb Unloading on Hamstring Muscle Activity in Rats. BRAIN, BEHAVIOR AND EVOLUTION 2024; 99:86-95. [PMID: 38412843 DOI: 10.1159/000537776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/04/2024] [Indexed: 02/29/2024]
Abstract
INTRODUCTION The changes in knee axial rotation play an important role in traumatic and non-traumatic knee disorders. It is known that support afferentation can affect the axial rotator muscles. The condition of innervation of the semitendinosus (ST) and biceps femoris posterior (BFp) has changed in non-terrestrial and terrestrial vertebrates in evolution; thus, we hypothesized this situation might be replayed by hindlimb unloading (HU). METHODS In the present study, the EMG activity of two hamstring muscles, m. ST and m. BFp, which are antagonists in axial rotation of the tibia, was examined before and after 7 days of HU. RESULTS During locomotion and swimming, the ST flexor burst activity increased in the stance-to-swing transition and in the retraction-protraction transition, respectively, while that of BFp remained unchanged. Both ST and BFp non-burst extensor activity increased during stepping and decreased during swimming. CONCLUSIONS Our results show that (1) the flexor burst activity of ST and BFp depends differently on the load-dependent sensory input in the step cycle; (2) shift of the activity gradient towards ST in the stance-to-swing transition could produce excessive internal tibia torque, which can be used as an experimental model of non-traumatic musculoskeletal disorders; and (3) the mechanisms of activity of ST and BFp may be based on reciprocal activity of homologous muscles in primary tetrapodomorph and depend on the increased role of supraspinal control.
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Affiliation(s)
- Alexander Popov
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Russian Federation,
| | | | - Oleg Gorskii
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Russian Federation
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
| | - Daria Kalinina
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
- Sirius National Technical University, Neuroscience Program, Sochi, Russian Federation
| | - Natalia Pavlova
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Russian Federation
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
| | - Pavel Musienko
- Pavlov Institute of Physiology RAS, Saint-Petersburg, Russian Federation
- Institute of Translational Biomedicine, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
- Life Improvement by Future Technologies Center "LIFT", Moscow, Russian Federation
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Alexander P, Vsevolod L, Natalia M, Pavel M. Effect of hindlimb unloading on recruitment of gastrocnemius medialis muscle during treadmill locomotion in rats. Exp Brain Res 2021; 239:2793-2801. [PMID: 34247266 DOI: 10.1007/s00221-021-06167-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 06/22/2021] [Indexed: 11/26/2022]
Abstract
After hindlimb unloading (HU), the adaptive changing of the rat step cycle duration, kinematics of the ankle and knee joints, and duration of one-joint ankle extensor m. soleus (SOL) activity are detected. However, how the activity of their synergist gastrocnemius medialis muscle (GM) changes in locomotion after HU remains unknown. GM is a two-joint muscle that produces both extension and flexion torques at the ankle and knee, respectively, regardless of the step cycle phase. The aim of our study was to assess changes in the flexor and extensor activity of GM and their influence on hindlimb kinematics after HU. The hindlimb kinematics, activity of GM, and SOL were evaluated, and semitendinosus muscle (ST) activity was registered in six Wistar rats in treadmill locomotion before and after HU. The mean EMG of the GM activity, which was co-active with ST burst activity, significantly increased after HU. The mean EMG of the GM activity, which was co-active with SOL activity, was unchanged after HU, but both SOL and GM bursts had a tendency to increase in duration. Hyperextension of the knee joint and the tendency to overextension of the ankle joint in the late of the stance phase were revealed after HU. The results show that the absence of weight bearing leads to an increase only in the flexor activity of GM and does not affect the extensor GM activity. Possible mechanisms of changes in GM activity and joint kinematics after HU are discussed.
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Affiliation(s)
- Popov Alexander
- Institute of Translational Biomedicine, Saint-Petersburg State University, Universitetskaya Emb., 7-9, Russia, Saint Petersburg, 199034
- Pavlov Institute of Physiology RAS, Makarov emb., 6, Russia, Saint Petersburg, 199034
| | | | - Merkulyeva Natalia
- Institute of Translational Biomedicine, Saint-Petersburg State University, Universitetskaya Emb., 7-9, Russia, Saint Petersburg, 199034
- Pavlov Institute of Physiology RAS, Makarov emb., 6, Russia, Saint Petersburg, 199034
| | - Musienko Pavel
- Institute of Translational Biomedicine, Saint-Petersburg State University, Universitetskaya Emb., 7-9, Russia, Saint Petersburg, 199034.
- Pavlov Institute of Physiology RAS, Makarov emb., 6, Russia, Saint Petersburg, 199034.
- Neuroscience Program, Sirius National Technical University, Olympic pr., 1, Russia, Sochi, 354340.
- Department of Nonpulmonary Tuberculosis, Institute of Phthysiopulmonology, Childrens Surgery and Orthopedic Clinic, Politekhnicheskaya ul. 32, Saint-Petersburg, 194064, Russia.
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