We hypothesized that considerable force reserve exists for the diaphragm muscle (DIAm) to generate transdiaphragmatic pressures (Pdi) necessary to sustain ventilation. In rats, we measured Pdi and DIAm EMG activity during different ventilatory (eupnea and hypoxia (10% O(2))-hypercapnia (5% CO(2))) and non-ventilatory (airway occlusion and sneezing induced by intranasal capsaicin) behaviors. Compared to maximum Pdi (Pdi(max) generated by bilateral phrenic nerve stimulation), the Pdi generated during eupnea (21+/-2%) and hypoxia-hypercapnia (28+/-4%) were significantly less (p<0.0001) than that generated during airway occlusion (63+/-4%) and sneezing (94+/-5%). The Pdi generated during spontaneous sighs was 62+/-5% of Pdi(max). Relative DIAm EMG activity (root mean square [RMS] amplitude) paralleled the changes in Pdi during different ventilatory and non-ventilatory behaviors (r(2)=0.78; p<0.0001). These results support our hypothesis of a considerable force reserve for the DIAm to accomplish ventilatory behaviors. A model for DIAm motor unit recruitment predicted that ventilatory behaviors would require activation of only fatigue resistant units.
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http://dx.doi.org/10.1016/j.resp.2010.07.001 | DOI Listing |
Muscle Nerve
January 2025
Department of Anatomy, Federal University of Alfenas (UNIFAL-MG), Alfenas, Brazil.
Introduction/aims: Duchenne muscular dystrophy (DMD) is caused by pathogenic variants in the DMD gene, making muscle fibers susceptible to contraction-induced membrane damage. Given the potential beneficial action of cannabidiol (CBD), we evaluated the in vitro effect of full-spectrum CBD oil on the viability of dystrophic muscle fibers and the in vivo effect on myopathy of the mdx mouse, a DMD model.
Methods: In vitro, dystrophic cells from the mdx mouse were treated with full-spectrum CBD oil and assessed with cell viability and cytotoxic analyses.
J Spinal Cord Med
January 2025
Speech-Language-Hearing Sciences, Medical School, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Introduction: Spinal cord injury is a physiological disruption often caused by trauma, leading to severe physical and psychological effects, including irreversible impairment and disability. Cervical injuries, particularly between C1 and C8, are the most severe, potentially causing diaphragm paralysis and requiring mechanical ventilation. Reduced respiratory muscle strength not only affects respiratory function but also significantly impacts voice, speech, and communication, which are crucial for quality of life.
View Article and Find Full Text PDFPflugers Arch
January 2025
Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 2/31 Lobachevsky St, Kazan, 420111, RT, Russia.
Many synaptic vesicles undergo exocytosis in motor nerve terminals during neuromuscular communication. Endocytosis then recovers the synaptic vesicle pool and presynaptic membrane area. The kinetics of endocytosis may shape neuromuscular transmission, determining its long-term reliability.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Anesthesiology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, No.600 Yishan Road, Xuhui District, Shanghai, 200233, People's Republic of China.
Regional anesthesia is a popular method for surgical anesthesia in clavicular surgery. Selective blocking of the cervical 3, 4, and 5 nerve roots shows promise in clavicle surgery, with its fast onset, good anesthesia and less complications, necessitating evaluation of its impact on diaphragmatic function. The purpose of this study is to examine the safety of C3, 4, and 5 nerve root block for its application in clavicle surgery.
View Article and Find Full Text PDFHum Mol Genet
December 2024
Center for Motor Neuron Biology and Disease, Columbia University Medical Center, 630 W. 168th St., New York, NY 10032, United States.
Spinal muscular atrophy (SMA) is caused by low levels of the survival motor neuron (SMN) protein. Even though SMN is ubiquitously expressed, the disease selectively affects motor neurons, leading to progressive muscle weakness. Even among motor neurons, certain motor units appear more clinically resistant to SMA.
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