Biomaterial Database

Expression of small-conductance calcium-activated potassium channels (SK) in outer hair cells of the rat cochlea. 1998

D Dulon, and L Luo, and C Zhang, and A F Ryan

Department of Surgery, UCSD School of Medicine, La Jolla, California 92093-0666, USA. didier.dulon@bordeaux.inserm.fr

Physiological evidence suggests that SK-type Ca2+-activated K+ channels participate in ACh-induced hyperpolarization of OHCs (outer hair cells). Based on the sequences published by Kohler et al. [(1996), Science, 273: 1709), we designed degenerated primers recognizing cDNA subunits of rSK1, rSK2 and rSK3. Using this consensus set of primers, we probed by PCR a rat organ of Corti cDNA library. Two PCR products of 707 base pairs with sequence identical to rSK3 and rSK2 were obtained and cloned to generate RNA probes for in situ hybridization in the rat cochlea. The subunit rSK2 showed hybridization in the organ of Corti, at the location of the OHCs. The expression of rSK2 by OHCs was confirmed by probing with PCR a poly(A) amplified OHC cDNA library. During development, rSK2 hybridization in the organ of Corti was negative at embryonic days E16, E18 and at P0, weak at P4 and stronger from P8 to adulthood. The subunit rSK2 could also be detected in the spiral ganglion from P4 to the adult stage. Contrary to rSK2, the subunit rSK3 did not show specific hybridization in the organ of Corti at the adult stage (P120) and only a weak expression was observed at P10 and P21. Our study demonstrates expression of rSK2 in OHCs. These potassium channels are good candidates to underlie the ACh-activated K+ currents recorded during patch-clamp recordings in isolated OHCs. The expression of rSK2 in the cochlear ganglion at the adult stage suggests that SK Ca2+-activated K+ channels may also participate in the repolarization of the auditory neurons after the action potential and may influence their firing patterns.

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
D009925	Organ of Corti	The spiral EPITHELIUM containing sensory AUDITORY HAIR CELLS and supporting cells in the cochlea. Organ of Corti, situated on the BASILAR MEMBRANE and overlaid by a gelatinous TECTORIAL MEMBRANE, converts sound-induced mechanical waves to neural impulses to the brain.	Basilar Papilla,Corti's Organ,Spiral Organ,Corti Organ,Cortis Organ,Organ, Corti's,Organ, Spiral,Organs, Spiral,Papilla, Basilar,Spiral Organs
D010275	Parasympathetic Nervous System	The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.	Nervous System, Parasympathetic,Nervous Systems, Parasympathetic,Parasympathetic Nervous Systems,System, Parasympathetic Nervous,Systems, Parasympathetic Nervous
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
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D003051	Cochlea	The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.	Cochleas
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
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription
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
D016133	Polymerase Chain Reaction	In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.	Anchored PCR,Inverse PCR,Nested PCR,PCR,Anchored Polymerase Chain Reaction,Inverse Polymerase Chain Reaction,Nested Polymerase Chain Reaction,PCR, Anchored,PCR, Inverse,PCR, Nested,Polymerase Chain Reactions,Reaction, Polymerase Chain,Reactions, Polymerase Chain