Membrane proteins involved in potassium shifts during muscle activity and fatigue

2006 ◽  
Vol 290 (3) ◽  
pp. R766-R772 ◽  
Author(s):  
Michael Kristensen ◽  
Thomas Hansen ◽  
Carsten Juel
Keyword(s):  
Electrical Stimulation ◽  
Muscle Activity ◽  
Muscle Force ◽  
Peak Force ◽  
Transport Capacity ◽  
Sarcolemmal Membrane ◽  
Male Wistar Rats ◽  
T Tubules ◽  
Kir2.1 Channel ◽  
Stimulation Of

Muscle activity is associated with potassium displacements, which may cause fatigue. It was reported previously that the density of the large-conductance Ca2+-dependent K+ (BKCa) channel is higher in the T tubule membrane than in the sarcolemmal membrane and that the opposite is the case for the ATP-sensitive K+ (KATP) channel. In the present experiments, we investigated the subcellular localizations of the strong inward rectifier 2.1 K+ (Kir2.1) channel and the Na+-K+-2Cl− (NKCC)1 cotransporter with Western blot analysis of different muscle fractions. Furthermore, muscle function was studied while trying to manipulate the opening probability or transport capacity of these proteins during electrical stimulation of isolated soleus muscles. All experiments were made with excised muscle from male Wistar rats. Kir2.1 channels were almost undetectable in the sarcolemmal membrane but present in the T tubule membrane, whereas NKCC1 cotransporters were present in the sarcolemmal membrane. For muscles incubated in a buffer containing pinacidil, NS1619, Ba2+, or bumetanide, there was a faster reduction in peak force ( P < 0.05). Furthermore, bumetanide incubation reduced the peak force at the onset of electrical stimulation ( P < 0.05). Thus the effects on muscle force indicate that these drugs can affect K+-transporting proteins and thereby influence K+ accumulation, especially in the T tubules, suggesting that KATP and BKCa channels are responsible for K+ release and decrease in force during repeated muscle contractions, whereas Kir2.1 and NKCC1 may have a role in K+ reuptake.

scholarly journals Asymmetry of reinforcing properties of the lateral hypothalamus in the self-stimulation test

2018 ◽  
Vol 16 (2) ◽  
pp. 37-41
Author(s):  
Nikolay S Efimov ◽  
Yulia N Bessolova ◽  
Inessa V Karpova ◽  
Andrei A Lebedev ◽  
Petr D Shabanov
Keyword(s):  
Electrical Stimulation ◽  
Lateral Hypothalamus ◽  
The Self ◽  
Stimulation Test ◽  
Reinforcing Agent ◽  
Male Wistar Rats ◽  
Left And Right ◽  
The Right ◽  
Self Stimulation ◽  
Stimulation Of

In the protocols of modern pharmacological studies of a self-stimulation reaction in rodents, stimulating electrodes are implanted as a rule unilaterally. The reinforcing properties of the left and right hypothalamus were suggested to be identical. The aim of the study was to clear up if the possibilities of the left and right hypothalamus to produce self-stimulation are similar or not. Methods. The study was carried out on adult male Wistar rats. The electrodes were implanted into the lateral hypothalamus bilaterally. The rats, in which an approach reaction was observed, learned self-stimulation in the Skinner box with stimulation of the left or right hypothalamus as a reinforcing agent descending thresholds of stimulation up to minimal one. Results. Self-stimulation of the left hypothalamus gave an approach reaction in the majority of rats (81.8%), self-stimulation reaction was developed in 72.7% of rats. Only 46.2% rats reacted on stimulation of the right hypothalamus, self-stimulation reaction was developed in 30.8% of rats. The thresholds of positive and negative reactions registered after electrical stimulation of both sides of hypothalamus were significantly differed (H(3, N = 31) = 14,92; p = 0,002). And these changes were not connected with lateralization but with sign of reaction: in general the thresholds of approach reaction were higher than thresholds of avoidance. Conclusion. In the paper, the fact of different possibility of approach reaction and self-stimulation development as a result of electrical stimulation of the left and right hypothalamus in rats has been described. After stimulation of the left hypothalamus, a possibility to receive positive reaction and to form self-stimulation on its basis is higher than after stimulation of the right hypothalamus. (For citation: Efimov NS, Bessolova YN, Karpova IV, et al. Asymmetry of reinforcing properties of the lateral hypothalamus in the self-stimulation test. Reviews on Clinical Pharmacology and Drug Therapy. 2018;16(2):37-41. doi: 10.17816/RCF16237-41).

scholarly journals Advantages of imaging photoplethysmography for migraine modeling: new optical markers of trigemino‐vascular activation in rats

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Alexey Y. Sokolov ◽  
Maxim A. Volynsky ◽  
Valery V. Zaytsev ◽  
Anastasiia V. Osipchuk ◽  
Alexei A. Kamshilin
Keyword(s):  
Blood Flow ◽  
Electrical Stimulation ◽  
Imaging System ◽  
Inhibitory Effect ◽  
Trigeminovascular System ◽  
Cranial Window ◽  
Arterial Blood ◽  
Male Wistar Rats ◽  
Optical Markers ◽  
Stimulation Of

Abstract Background Existent animal models of migraine are not without drawbacks and limitations. The aim of our study was to evaluate imaging photoplethysmography (PPG) as a method of assessing intracranial blood flow in rats and its changes in response to electrical stimulation of dural trigeminal afferents. Methods Experiments were carried out with 32 anesthetized adult male Wistar rats. Trigeminovascular system (TVS) was activated by means of electrical stimulation of dural afferents through a closed cranial window (CCW). Parameters of meningeal blood flow were monitored using a PPG imaging system under green illumination with synchronous recording of an electrocardiogram (ECG) and systemic arterial blood pressure (ABP). Two indicators related to blood-flow parameters were assessed: intrinsic optical signals (OIS) and the amplitude of pulsatile component (APC) of the PPG waveform. Moreover, we carried out pharmacological validation of these indicators by determining their sensitivity to anti-migraine drugs: valproic acid and sumatriptan. For statistical analysis the non-parametric tests with post-hoc Bonferroni correction was used. Results Significant increase of both APC and OIS was observed due to CCW electrical stimulation. Compared to saline (n = 11), intravenous administration of both the sumatriptan (n = 11) and valproate (n = 10) by using a cumulative infusion regimen (three steps performed 30 min apart) lead to significant inhibitory effect on the APC response to the stimulation. In contrast, intravenous infusion of any substance or saline did not affect the OIS response to the stimulation. It was found that infusion of either sumatriptan or valproate did not affect the response of ABP or heart rate to the stimulation. Conclusions Imaging PPG can be used in an animal migraine model as a method for contactless assessment of intracranial blood flow. We have identified two new markers of TVS activation, one of which (APC) was pharmacologically confirmed to be associated with migraine. Monitoring of changes in APC caused by CCW electrical stimulation (controlling efficiency of stimulation by OIS) can be considered as a new way to assess the peripheral mechanism of action of anti-migraine interventions.

scholarly journals Clinical, neurological, and neurophysiological evaluation of the efficiency of motor rehabilitation in children with cerebral palsy using robotic mechanotherapy and transcutaneous electrical stimulation of the spinal cord

2016 ◽  
Vol 4 (4) ◽  
pp. 47-55 ◽  
Author(s):  
Galina A. Ikoeva ◽  
Igor E. Nikityuk ◽  
Olga I. Kivoenko ◽  
Tatyana R. Moshonkina ◽  
Irina A. Solopova ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cerebral Palsy ◽  
Electrical Stimulation ◽  
Treatment Group ◽  
Motor Function ◽  
Muscle Activity ◽  
Spastic Diplegia ◽  
Transcutaneous Electrical Stimulation ◽  
Motor Rehabilitation ◽  
Stimulation Of

Introduction. Rehabilitation of patients with cerebral palsy (CP) remains a very difficult task. Stable and growing movement restrictions in such patients cause a life-long need for treatment and rehabilitation. Neurorehabilitation of children with CP at various stages includes not only traditional physical rehabilitation methods, but also extensive use of robotic mechanotherapy techniques and new technologies in the field of neurophysiology. One of such technology is non-invasive percutaneous electrical stimulation of the spinal cord.Aim of the study: To assess the effect of transcutaneous electrical stimulation of the spinal cord to improve the motor function of children with spastic diplegia using the “Lokomat” robotic mechanotherapy system.Materials and methods. A clinical rehabilitation study of 26 patients aged 6–12 years with CP was conducted. The treatment group included 11 patients who received one course of robotic mechanotherapy using the “Lokomat” system combined with transcutaneous electrical stimulation of the spinal cord. The control group included 15 patients who received one course of robotic mechanotherapy only.Results. A comparative analysis of the two groups based on the results of clinical examinations using specific scales (GMFCS, GMFM-88, Modified Ashworth Scale of Muscle Spasticity), locomotor tests (L-FORCE, L-ROM), and evaluations of muscle activity using electromyography showed that one course of rehabilitation resulted in improvement in motor function in all patients of both groups, but positive dynamics were more significant in the treatment group that underwent percutaneous electrical stimulation of the spinal cord.Conclusion. Based on clinical data, changes in indicators of the locomotor tests L-FORCE and L-ROM, as well as assessment of changes in muscle activity, showed that motor rehabilitation of children with spastic diplegia using the “Lokomat” robotic mechanotherapy system combined with transcutaneous electrical spinal cord stimulation was more effective than robotic mechanotherapy only.

scholarly journals Direct Electrical Stimulation of Premotor Areas: Different Effects on Hand Muscle Activity during Object Manipulation

2019 ◽  
Vol 30 (1) ◽  
pp. 391-405 ◽  
Author(s):  
Luca Fornia ◽  
Marco Rossi ◽  
Marco Rabuffetti ◽  
Antonella Leonetti ◽  
Guglielmo Puglisi ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Muscle Activity ◽  
Premotor Cortex ◽  
Object Manipulation ◽  
Awake Surgery ◽  
Direct Electrical Stimulation ◽  
Task Execution ◽  
Hand Muscles ◽  
Premotor Areas ◽  
Stimulation Of

Abstract Dorsal and ventral premotor (dPM and vPM) areas are crucial in control of hand muscles during object manipulation, although their respective role in humans is still debated. In patients undergoing awake surgery for brain tumors, we studied the effect of direct electrical stimulation (DES) of the premotor cortex on the execution of a hand manipulation task (HMt). A quantitative analysis of the activity of extrinsic and intrinsic hand muscles recorded during and in absence of DES was performed. Results showed that DES applied to premotor areas significantly impaired HMt execution, affecting task-related muscle activity with specific features related to the stimulated area. Stimulation of dorsal vPM induced both a complete task arrest and clumsy task execution, characterized by general muscle suppression. Stimulation of ventrocaudal dPM evoked a complete task arrest mainly due to a dysfunctional recruitment of hand muscles engaged in task execution. These results suggest that vPM and dPM contribute differently to the control of hand muscles during object manipulation. Stimulation of both areas showed a significant impact on motor output, although the different effects suggest a stronger relationship of dPM with the corticomotoneuronal circuit promoting muscle recruitment and a role for vPM in supporting sensorimotor integration.

Baroreceptor activation or glutamate coinjection facilitates depressor responses to ANF microinjection into NTS

1989 ◽  
Vol 257 (2) ◽  
pp. R405-R409
Author(s):  
D. J. McKitrick ◽  
F. R. Calaresu
Keyword(s):  
Electrical Stimulation ◽  
Significant Interaction ◽  
Cardiovascular Responses ◽  
Solitary Tract ◽  
Aortic Depressor Nerve ◽  
Male Wistar Rats ◽  
Threshold Doses ◽  
Baroreceptor Activation ◽  
Dorsal Medulla ◽  
Stimulation Of

As microinjection of atrial natriuretic factor (ANF) into the nucleus of the solitary tract (NTS) has been shown to elicit depressor responses [D. J. McKitrick and F. R. Calaresu. Am. J. Physiol. 255 (Regulatory Integrative Comp. Physiol. 24): R182-R187, 1988], we investigated the possibility that these responses might be facilitated either by electrical stimulation of arterial baroreceptor fibers in the aortic depressor nerve (ADN) or by simultaneous microinjection of L-glutamate (Glu) into the same sites in the NTS. Male Wistar rats (n = 51) were anesthetized with urethan (1.4 g/kg ip), artificially ventilated, and the dorsal medulla was exposed. The ADN was isolated, cut distally, and the central end was placed on bipolar stimulating electrodes. Threshold doses of 10(-7) M ANF microinjected into the NTS were combined with threshold electrical stimulation of the ADN (n = 37) or threshold doses of 0.13-0.5 M Glu (n = 14) microinjected into the NTS. There was a significant interaction between ANF microinjection and ADN stimulation in producing changes in mean arterial pressure (MAP) and heart rate [HR; P less than 0.05; -20.2 +/- 2.3 (SE) mmHg and -30.8 +/- 6.9 (SE) beats/min, respectively; n = 18]. There was also a significant interaction between ANF and Glu in producing changes in MAP and HR [P less than 0.05; -16.3 +/- 1.8 (SE) mmHg and -15.0 +/- 3.0 (SE) beats/min, respectively; n = 8]. These results indicate that ANF influences neurons in the NTS, which are also influenced by activation of arterial baroreceptors, and ANF and Glu interact in the NTS to produce facilitated cardiovascular responses.

scholarly journals The Mechanism of Tongue Projection in Chameleons: II. Role of Shape Change in a Muscular Hydrostat

1992 ◽  
Vol 168 (1) ◽  
pp. 23-40 ◽  
Author(s):  
PETER C. WAINWRIGHT ◽  
ALBERT F. BENNETT
Keyword(s):  
Electrical Stimulation ◽  
Muscle Activity ◽  
Shape Change ◽  
Morphological Features ◽  
Peak Force ◽  
Longitudinal Extension ◽  
Tapered Region

In this paper we investigate the interaction between the accelerator muscle (the muscle that powers tongue projection) and the entoglossal process (the tongue's skeletal support) that occurs during tongue projection in chamaeleonid lizards. Previous work has shown that there is a delay of about 185 ms between the onset of accelerator muscle activity and the onset of tongue projection. In conjunction with anatomical observations, in vitro preparations of the accelerator muscle mounted on isolated entoglossal and surrogate processes were stimulated tetanically, and the resulting movements were recorded on video at 200 fields s−1. Three results indicate that morphological features of the entoglossus and the accelerator muscle delay the onset of tongue projection following the onset of accelerator contraction: (1) the entoglossus is parallel-sided along the posterior 90% of its shaft, only tapering at the very tip, (2) the sphincter-like portion of the accelerator muscle, which effects tongue projection, makes up the posterior 63% of the muscle and does not contact the tapered region of the entoglossus at rest, and (3) accelerator muscles mounted on the entoglossus undergo longitudinal extension and lateral constriction for 83 ms following the onset of electrical stimulation, before projecting off the entoglossus. It is proposed that, during elongation of the accelerator muscle, the sphincter-like region ultimately comes into contact with the tapered region of the entoglossus, causing the onset of projection. This conclusion is supported by the observation that the time between the onset of stimulation and the onset of projection was longer in preparations with surrogate entoglossal processes that had no tapered tip and shorter with surrogate processes that had a tapered tip about four times as long as the natural entoglossus. Tetanically stimulated accelerator muscles reached 90% of peak force 110 ms after the onset of stimulation, indicating that the 185 ms delay between the onset of accelerator activity and the onset of projection seen in vivo allows the accelerator to achieve peak force prior to the onset of projection. Thus, the delay in projection may be crucial in maximizing the acceleration and velocity achieved by the projected chameleon tongue.

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