Biomaterial Database

Electrical resonance and membrane currents in turtle cochlear hair cells. 1986

J J Art, and A C Crawford, and R Fettiplace

The electrical and mechanical properties of single hair cells from the turtle's cochlea were examined to investigate the basis of their electrical resonance. Receptor potentials were measured with intracellular micropipettes in the isolated basilar papilla. At the onset and termination of a step displacement of the ciliary bundle the receptor potential showed a damped oscillation reflecting the frequency selectivity of the cell. Resonance frequencies increased systematically from apex to base of the cochlea. Similar oscillations could be elicited by a current step injected through the recording electrode. Solitary hair cells enzymatically isolated from the papilla were investigated with the tight-seal whole-cell recording method. Cells retained their properties in response to current steps and had resonance frequencies between 10 and 350 Hz. In voltage clamp such cells displayed a large outward K+ current and an inward Ca2+ current both activated by depolarization from the resting potential. The relaxation time constant of the K+ current was inversely correlated with the resonance frequency of the cell, varying from 150 ms in the lowest frequency cells to less than 1 ms in the highest ones. It is argued that variation in the kinetics of this current is the major factor responsible for the range of resonance frequencies. In preparations of the isolated papilla a flexible glass fibre, attached to the tip of a ciliary bundle, was used to deliver constant force steps to the bundle and to monitor its displacement. Receptor potentials were simultaneously recorded. At the beginning and end of a force step towards the kinocilium, the bundle vibrated at a frequency which coincided with the electrical resonance frequency of the cell.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D009431	Neural Conduction	The propagation of the NERVE IMPULSE along the nerve away from the site of an excitation stimulus.	Nerve Conduction,Conduction, Nerve,Conduction, Neural,Conductions, Nerve,Conductions, Neural,Nerve Conductions,Neural Conductions
D010898	Pitch Perception	A dimension of auditory sensation varying with cycles per second of the sound stimulus.	Perception, Pitch,Perceptions, Pitch,Pitch Perceptions
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D006198	Hair Cells, Auditory	Sensory cells in the organ of Corti, characterized by their apical stereocilia (hair-like projections). The inner and outer hair cells, as defined by their proximity to the core of spongy bone (the modiolus), change morphologically along the COCHLEA. Towards the cochlear apex, the length of hair cell bodies and their apical STEREOCILIA increase, allowing differential responses to various frequencies of sound.	Auditory Hair Cells,Cochlear Hair Cells,Auditory Hair Cell,Cell, Cochlear Hair,Cells, Cochlear Hair,Cochlear Hair Cell,Hair Cell, Auditory,Hair Cell, Cochlear,Hair Cells, Cochlear
D006309	Hearing	The ability or act of sensing and transducing ACOUSTIC STIMULATION to the CENTRAL NERVOUS SYSTEM. It is also called audition.	Audition
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001489	Basilar Membrane	A basement membrane in the cochlea that supports the hair cells of the ORGAN OF CORTI, consisting keratin-like fibrils. It stretches from the SPIRAL LAMINA to the basilar crest. The movement of fluid in the cochlea, induced by sound, causes displacement of the basilar membrane and subsequent stimulation of the attached hair cells which transform the mechanical signal into neural activity.	Basilar Membranes,Membrane, Basilar,Membranes, Basilar
D001703	Biophysics	The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.	Mechanobiology