Effects of Electrical Pulse Polarity Shape on Intra Cochlear Neural Responses in Humans: Triphasic Pulses with Anodic and Cathodic Second Phase

Modern cochlear implants employ charge-balanced biphasic and triphasic pulses. However, the effectiveness of electrical pulse shape and polarity is still a matter of debate. For this purpose, in a previous study (Bahmer & Baumann, 2013) electrophysiological and psychophysical measurement after triphasic pulse stimulation with cathodic second phase was determined. Depending on the pulse shape configuration, the stimulation effectiveness differed similarly for electrophysiological and psychophysical measurements. However, the experiments were limited to stimulation pulses with cathodic second phase. In this study, cathodic and anodic second phase stimulation was applied. Evoked compound action potentials (ECAPs) and psychophysical responses were recorded in eleven cochlear implant recipients (SYNCHRONY/SONATAti100/PULSARci100 devices, MED-EL Innsbruck). We compared the strength of the ECAP responses with individual psychophysical threshold levels depending on the pulse shape. Results for pulses with cathodic second phase showed the weakest ECAP response and highest psychophysical thresholds for symmetric triphasic pulse shapes, and the strongest ECAP response and lowest psychophysical thresholds for biphasic pulses. The ECAP responses for anodic second phase differed from the results of triphasic stimulation with cathodic second phase. The U-shape of the ECAP response with increasing phase amplitude ratio (PAR) for cathodic second phase could not be observed for the anodic second phase. Instead, a flat curve was observed. In contrast, psychophysical threshold curves with increasing PAR were similar between cathodic and anodic second phase stimulation.

Download Full-text

Effects of Electrical Pulse Polarity Shape on Intra Cochlear Neural Responses in Humans: Triphasic Pulses with Anodic and Cathodic Second Phase

Hearing Research ◽

10.1016/j.heares.2021.108375 ◽

2021 ◽

pp. 108375

Author(s):

Katharina V.A. Kretzer ◽

David P. Herrmann ◽

Sabrina H. Pieper ◽

Andreas Bahmer

Keyword(s):

Electrical Pulse ◽

Second Phase ◽

Neural Responses ◽

Pulse Polarity

Download Full-text

Effects of electrical pulse polarity shape on intra cochlear neural responses in humans: Triphasic pulses with cathodic second phase

Hearing Research ◽

10.1016/j.heares.2013.10.001 ◽

2013 ◽

Vol 306 ◽

pp. 123-130 ◽

Cited By ~ 11

Author(s):

Andreas Bahmer ◽

Uwe Baumann

Keyword(s):

Electrical Pulse ◽

Second Phase ◽

Neural Responses ◽

Pulse Polarity

Download Full-text

Electrical pulse stimulation induces differential responses in insulin action in myotubes from severely obese individuals

The Journal of Physiology ◽

10.1113/jp276990 ◽

2018 ◽

Vol 597 (2) ◽

pp. 449-466 ◽

Cited By ~ 8

Author(s):

Sanghee Park ◽

Kristen D. Turner ◽

Donghai Zheng ◽

Jeffrey J. Brault ◽

Kai Zou ◽

...

Keyword(s):

Insulin Action ◽

Electrical Pulse ◽

Electrical Pulse Stimulation ◽

Severely Obese ◽

Differential Responses ◽

Pulse Stimulation

Download Full-text

Electrical Pulse Stimulation of Primary Human Skeletal Muscle Cells

Methods in Molecular Biology - Myogenesis ◽

10.1007/978-1-4939-8897-6_2 ◽

2018 ◽

pp. 17-24 ◽

Cited By ~ 4

Author(s):

Nataša Nikolić ◽

Vigdis Aas

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Muscle Cells ◽

Skeletal Muscle Cells ◽

Electrical Pulse ◽

Electrical Pulse Stimulation ◽

Human Skeletal Muscle Cells ◽

Pulse Stimulation ◽

Stimulation Of

Download Full-text

Transcriptome Analyses of In Vitro Exercise Models by Clenbuterol Supplementation or Electrical Pulse Stimulation

Applied Sciences ◽

10.3390/app112110436 ◽

2021 ◽

Vol 11 (21) ◽

pp. 10436

Author(s):

Taku Fukushima ◽

Miho Takata ◽

Ayano Kato ◽

Takayuki Uchida ◽

Takeshi Nikawa ◽

...

Keyword(s):

Gene Ontology ◽

Electrical Pulse ◽

C2c12 Myotubes ◽

Rna Seq ◽

Gene Expressions ◽

Beneficial Effects ◽

Electrical Pulse Stimulation ◽

Transcriptional Changes ◽

Pulse Stimulation

Exercise has beneficial effects on human health and is affected by two different pathways; motoneuron and endocrine. For the advancement of exercise research, in vitro exercise models are essential. We established two in vitro exercise models using C2C12 myotubes; EPS (electrical pulse stimulation) for a motoneuron model and clenbuterol, a specific β2 adrenergic receptor agonist, treatment for an endocrine model. For clenbuterol treatment, we found that Ppargc1a was induced only in low glucose media (1 mg/mL) using a 1-h treatment of 30 ng/mL clenbuterol. Global transcriptional changes of clenbuterol treatment were analyzed by RNA-seq and gene ontology analyses and indicated that mitogenesis and the PI3K-Akt pathway were enhanced, which is consistent with the effects of exercise. Cxcl1 and Cxcl5 were identified as candidate myokines induced by adrenaline. As for the EPS model, we compared 1 Hz of 1-pulse EPS and 1 Hz of 10-pulse EPS for 24 h and determined Myh gene expressions. Ten-pulse EPS induced higher Myh2 and Myh7 expression. Global transcriptional changes of 10-pulse EPS were also analyzed using RNA-seq, and gene ontology analyses indicated that CaMK signaling and hypertrophy pathways were enhanced, which is also consistent with the effects of exercise. In this paper, we provided two transcriptome results of in vitro exercise models and these databases will contribute to advances in exercise research.

Download Full-text

Effect of differentiation, de novo innervation, and electrical pulse stimulation on mRNA and protein expression of Na+,K+-ATPase, FXYD1, and FXYD5 in cultured human skeletal muscle cells

PLoS ONE ◽

10.1371/journal.pone.0247377 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0247377

Author(s):

Vid Jan ◽

Katarina Miš ◽

Natasa Nikolic ◽

Klemen Dolinar ◽

Metka Petrič ◽

...

Keyword(s):

Skeletal Muscle ◽

Mrna Expression ◽

Human Skeletal Muscle ◽

De Novo ◽

Muscle Cells ◽

Electrical Pulse ◽

Electrical Pulse Stimulation ◽

Human Skeletal Muscle Cells ◽

Pulse Stimulation ◽

Low Serum

Denervation reduces the abundance of Na+,K+-ATPase (NKA) in skeletal muscle, while reinnervation increases it. Primary human skeletal muscle cells, the most widely used model to study human skeletal muscle in vitro, are usually cultured as myoblasts or myotubes without neurons and typically do not contract spontaneously, which might affect their ability to express and regulate NKA. We determined how differentiation, de novo innervation, and electrical pulse stimulation affect expression of NKA (α and β) subunits and NKA regulators FXYD1 (phospholemman) and FXYD5 (dysadherin). Differentiation of myoblasts into myotubes under low serum conditions increased expression of myogenic markers CD56 (NCAM1), desmin, myosin heavy chains, dihydropyridine receptor subunit α1S, and SERCA2 as well as NKAα2 and FXYD1, while it decreased expression of FXYD5 mRNA. Myotubes, which were innervated de novo by motor neurons in co-culture with the embryonic rat spinal cord explants, started to contract spontaneously within 7–10 days. A short-term co-culture (10–11 days) promoted mRNA expression of myokines, such as IL-6, IL-7, IL-8, and IL-15, but did not affect mRNA expression of NKA, FXYDs, or myokines, such as musclin, cathepsin B, meteorin-like protein, or SPARC. A long-term co-culture (21 days) increased the protein abundance of NKAα1, NKAα2, FXYD1, and phospho-FXYD1Ser68 without attendant changes in mRNA levels. Suppression of neuromuscular transmission with α-bungarotoxin or tubocurarine for 24 h did not alter NKA or FXYD mRNA expression. Electrical pulse stimulation (48 h) of non-innervated myotubes promoted mRNA expression of NKAβ2, NKAβ3, FXYD1, and FXYD5. In conclusion, low serum concentration promotes NKAα2 and FXYD1 expression, while de novo innervation is not essential for upregulation of NKAα2 and FXYD1 mRNA in cultured myotubes. Finally, although innervation and EPS both stimulate contractions of myotubes, they exert distinct effects on the expression of NKA and FXYDs.

Download Full-text