Electrical stimulation of cardiac tissue by a bipolar electrode in a conductive bath

SUMMARY Experiments were undertaken to localize those hypothalamic areas in the male quail (Coturnix coturnix japonica) where electrical stimulation would increase LH secretion. The posterior basal hypothalamus was stimulated with rectangular pulses (height 500 μA) through a bipolar electrode for 6 min, blood samples being taken for LH assay 20 min before, and 2, 10, 20 and 30 min after stimulation. The highest plasma concentration was observed in the 2 min sample. Over the next 30 min the LH level decreased to the resting concentration. The relative increase in LH level was greatest in sexually immature quail and least in photostimulated castrated birds, although the highest absolute levels were seen in the castrated quail. There were no statistical differences between the magnitude of the LH increases in sexually immature, mature and castrated quail. Various hypothalamic regions were then stimulated with a smaller current (200 μA) applied for only 2 min. A highly significant rise in LH followed stimulation of either the tuberal hypothalamus (postero-dorsal part of the infundibular nuclear complex, PD-INC), or the preoptic region (POR) while stimulation 0·5–1·5 mm away from these regions did not change LH secretion. Stimulation of the anterior basal hypothalamus, or of the suprachiasmatic area, caused a significant rise in LH concentration although this was less than that seen after stimulation of the POR. Stimulation in the POR or the PD-INC was ineffective if the tuberal hypothalamus had been deafferentated surgically some days previously. The data complement the studies in which destruction of the PD-INC or the POR by electrolytic lesions has been shown to block photoperiodically induced testicular growth and LH secretion.

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Development of a thin-film porous-microelectrode array (p-mea) for electrical stimulation of engineered cardiac tissue.

10.18297/etd/1736 ◽

2014 ◽

Author(s):

Hiren Trada

Keyword(s):

Thin Film ◽

Electrical Stimulation ◽

Microelectrode Array ◽

Cardiac Tissue ◽

Stimulation Of

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Binocular 3D otolith-ocular reflexes: responses of chinchillas to prosthetic electrical stimulation targeting the utricle and saccule

Journal of Neurophysiology ◽

10.1152/jn.00883.2018 ◽

2020 ◽

Vol 123 (1) ◽

pp. 259-276 ◽

Cited By ~ 5

Author(s):

Kristin N. Hageman ◽

Margaret R. Chow ◽

Dale Roberts ◽

Peter J. Boutros ◽

Angela Tooker ◽

...

Keyword(s):

Electrical Stimulation ◽

Hair Cells ◽

Temporal Dynamics ◽

Semicircular Canals ◽

Bipolar Electrode ◽

Electrode Arrays ◽

Reflex Responses ◽

Ocular Reflex ◽

Postural Responses ◽

Stimulation Of

From animal experiments by Cohen and Suzuki et al. in the 1960s to the first-in-human clinical trials now in progress, prosthetic electrical stimulation targeting semicircular canal branches of the vestibular nerve has proven effective at driving directionally appropriate vestibulo-ocular reflex eye movements, postural responses, and perception. That work was considerably facilitated by the fact that all hair cells and primary afferent neurons in each canal have the same directional sensitivity to head rotation, the three canals’ ampullary nerves are geometrically distinct from one another, and electrically evoked three-dimensional (3D) canal-ocular reflex responses approximate a simple vector sum of linearly independent components representing relative excitation of each of the three canals. In contrast, selective prosthetic stimulation of the utricle and saccule has been difficult to achieve, because hair cells and afferents with many different directional sensitivities are densely packed in those endorgans and the relationship between 3D otolith-ocular reflex responses and the natural and/or prosthetic stimuli that elicit them is more complex. As a result, controversy exists regarding whether selective, controllable stimulation of electrically evoked otolith-ocular reflexes (eeOOR) is possible. Using micromachined, planar arrays of electrodes implanted in the labyrinth, we quantified 3D, binocular eeOOR responses to prosthetic electrical stimulation targeting the utricle, saccule, and semicircular canals of alert chinchillas. Stimuli delivered via near-bipolar electrode pairs near the maculae elicited sustained ocular countertilt responses that grew reliably with pulse rate and pulse amplitude, varied in direction according to which stimulating electrode was employed, and exhibited temporal dynamics consistent with responses expected for isolated macular stimulation. NEW & NOTEWORTHY As the second in a pair of papers on Binocular 3D Otolith-Ocular Reflexes, this paper describes new planar electrode arrays and vestibular prosthesis architecture designed to target the three semicircular canals and the utricle and saccule. With this technological advancement, electrically evoked otolith-ocular reflexes due to stimulation via utricle- and saccule-targeted electrodes were recorded in chinchillas. Results demonstrate advances toward achieving selective stimulation of the utricle and saccule.

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Development of a new experimental model of intramuscular electrical stimulation of the diaphragm in rabbits

Acta Cirurgica Brasileira ◽

10.1590/s0102-86502010000600003 ◽

2010 ◽

Vol 25 (6) ◽

pp. 475-478 ◽

Cited By ~ 3

Author(s):

Rodrigo Guellner Ghedini ◽

Ane Margarites ◽

Elaine Aparecida Felix ◽

Rogério Gastal Xavier ◽

Cristiano Feijó Andrade

Keyword(s):

Mechanical Ventilation ◽

Animal Model ◽

Electrical Stimulation ◽

Ventilatory Support ◽

Current Intensity ◽

Bipolar Electrode ◽

Minute Interval ◽

The Relationship ◽

Diaphragmatic Stimulation ◽

Stimulation Of

PURPOSE: To develop an animal model of diaphragmatic electrical stimulation able to generate an appropriate ventilatory support through the direct implantation of electrodes in the diaphragm (electroventilation). METHODS: Six New Zealand female rabbits (2-3 kg) were placed on mechanical ventilation. Then, a laparotomy was performed in order to identify the motor points in each hemidiaphragm, followed by the implantation of the electrodes for diaphragmatic stimulation. We tested two types of electrodes according to the conduction of electrical stimulation: unipolar and bipolar. The electrodes were placed on different occasions in the same animals and tested with current intensities of 20, 26 and 32 mA. Each current intensity was repeated three times for 10 respiratory cycles with 1 minute interval between each cycle, and 5 minutes for new current intensity. We recorded the relationship between current intensity and inspiratory volume. RESULTS: The electrodes adequately stimulate the diaphragm and obtain inspired volumes using different intensity currents. The bipolar electrode generated inspiratory volumes as high as 4.5 times of baseline while the unipolar electrode reached up to 3.5 times of baseline. CONCLUSION: This model has proved to be effective for studying the performance of the diaphragm under different electrical stimulations using different set of electrodes.

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