Electrophysiology and pharmacology of outward potassium currents in semicircular canal hair cells of toadfish, Opsanus tau. 1997

A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, USA. toni@tfneuron.wustl.edu

Outward currents from hair cells from the horizontal semicircular canal (HSCC) of the toadfish were investigated using whole cell patch clamp methods. Two classes of hair cells are found. One class (approx. 10% of cells) showed only a non-inactivating current (IKCa) which was blocked by 2 mM TEA. A second class had both inactivating and non-inactivating currents. The former (IA) was blocked by 4-AP (1 mM) and the latter (IKCa) by TEA (2-20 mM) . While the majority of the cells expressed both these outward currents, due to IA inactivation both currents are functionally present in the same cell only between -60 and -40 mV. At more depolarized membrane potentials, IA was inactivated, suggesting that a single hair cell may have two distinct signalling modes, one dominated by IA at more hyperpolarized membrane potentials and the other by IKCa at depolarized values where ICa is beginning to grow, increasing both amplitude and activation rate of IKCa. The switch between modes will be determined by the amplitude and frequency characteristics of the stimulus and possibly also by actions of efferent transmitters. In current clamp mode, 10% of the HSCC hair cells showed high Q and high frequency resonance, from 44 to 360 Hz at 12 degrees C. These cells expressed only one outward calcium dependent, non-inactivating, TEA sensitive current, characteristic of IKCa. A suggested role for high frequency resonance is as positive feedback to produce a high frequency updating of the stereociliary compliance to most faithfully transduce angular acceleration.

UI MeSH Term Description Entries
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
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
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.
D005399 Fishes A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.
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
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
D012444 Saccule and Utricle Two membranous sacs within the vestibular labyrinth of the INNER EAR. The saccule communicates with COCHLEAR DUCT through the ductus reuniens, and communicates with utricle through the utriculosaccular duct from which the ENDOLYMPHATIC DUCT arises. The utricle and saccule have sensory areas (acoustic maculae) which are innervated by the VESTIBULAR NERVE. Otolithic Organs,Utricle,Saccule,Organ, Otolithic,Otolithic Organ,Saccules,Utricle and Saccule,Utricles
D012665 Semicircular Canals Three long canals (anterior, posterior, and lateral) of the bony labyrinth. They are set at right angles to each other and are situated posterosuperior to the vestibule of the bony labyrinth (VESTIBULAR LABYRINTH). The semicircular canals have five openings into the vestibule with one shared by the anterior and the posterior canals. Within the canals are the SEMICIRCULAR DUCTS. Semi-Circular Canals,Canal, Semi-Circular,Canal, Semicircular,Semi Circular Canals,Semi-Circular Canal,Semicircular Canal
D015221 Potassium Channels Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits. Ion Channels, Potassium,Ion Channel, Potassium,Potassium Channel,Potassium Ion Channels,Channel, Potassium,Channel, Potassium Ion,Channels, Potassium,Channels, Potassium Ion,Potassium Ion Channel
D015761 4-Aminopyridine One of the POTASSIUM CHANNEL BLOCKERS with secondary effect on calcium currents which is used mainly as a research tool and to characterize channel subtypes. 4-Aminopyridine Sustained Release,Dalfampridine,Fampridine-SR,Pymadine,VMI-103,4 Aminopyridine,4 Aminopyridine Sustained Release,Fampridine SR,Sustained Release, 4-Aminopyridine,VMI 103,VMI103

Related Publications

A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
February 1996, Journal of neurophysiology,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
August 1999, The Journal of comparative neurology,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
May 1990, The Journal of neuroscience : the official journal of the Society for Neuroscience,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
October 1994, The Biological bulletin,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
December 1998, The Journal of comparative neurology,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
July 1997, The Journal of comparative neurology,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
November 1991, Journal of neurophysiology,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
January 1994, Journal of neurophysiology,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
January 1990, Hearing research,
A Steinacker, and J Monterrubio, and R Perez, and A F Mensinger, and A Marin
October 2001, The Biological bulletin,
Copied contents to your clipboard!