Biomaterial Database

Efferent neurotransmitters and intracellular Ca2+ concentrations in inner hair cells of guinea pig. 1993

T Yamashita, and H Amano, and T Kumazawa

Department of Otolaryngology, Kansai Medical University, Osaka, Japan.

To elucidate efferent inhibitory mechanisms of the cochlear inner hair cells (IHCs), the effects of candidate efferent neurotransmitters on intracellular Ca2+ concentrations ([Ca2+]i) in the isolated IHCs of guinea pig were determined using the Ca2+ sensitive dye fura-2 and digital imaging microscopy. In the presence of 1 mM acetylcholine (ACh), there was a gradual and reversible increase in [Ca2+]i. In the presence of 10 microM ATP, there was a rapid and marked rise in [Ca2+]i. Thus, both ACh and ATP seem to be efferent neurotransmitters in IHCs of guinea pig. The ATP-induced elevation of [Ca2+]i in IHCs was suppressed when ACh was concomitantly applied; therefore, ACh may act as an antagonist of ATP-induced Ca2+ entry. With the independent addition of 10 microM calcitonin gene-related peptide and 10 microM enkephalin, there were no significant increases in [Ca2+]i. These neuropeptides are putative candidates for the efferent neuromodulators in IHCs of the guinea pig.

UI	MeSH Term	Description	Entries
D009476	Neurons, Efferent	Neurons which send impulses peripherally to activate muscles or secretory cells.	Efferent Neurons,Efferent Neuron,Neuron, Efferent
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
D004745	Enkephalins	One of the three major families of endogenous opioid peptides. The enkephalins are pentapeptides that are widespread in the central and peripheral nervous systems and in the adrenal medulla.	Enkephalin
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006199	Hair Cells, Auditory, Inner	Auditory sensory cells of organ of Corti, usually placed in one row medially to the core of spongy bone (the modiolus). Inner hair cells are in fewer numbers than the OUTER AUDITORY HAIR CELLS, and their STEREOCILIA are approximately twice as thick as those of the outer hair cells.	Auditory Hair Cell, Inner,Auditory Hair Cells, Inner,Cochlear Inner Hair Cell,Cochlear Inner Hair Cells,Hair Cell, Auditory, Inner,Inner Auditory Hair Cell,Inner Auditory Hair Cells,Inner Hair Cells,Cell, Inner Hair,Cells, Inner Hair,Hair Cell, Inner,Hair Cells, Inner,Inner Hair Cell
D000109	Acetylcholine	A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.	2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
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
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse
D015740	Calcitonin Gene-Related Peptide	A 37-amino acid peptide derived from the calcitonin gene. It occurs as a result of alternative processing of mRNA from the calcitonin gene. The neuropeptide is widely distributed in the brain, gut, perivascular nerves, and other tissue. The peptide produces multiple biological effects and has both circulatory and neurotransmitter modes of action. In particular, it is a potent endogenous vasodilator.	Calcitonin Gene-Related Peptide I,Calcitonin Gene-Related Peptide II,alpha-CGRP,alpha-Calcitonin Gene-Related Peptide,beta-CGRP,beta-Calcitonin Gene-Related Peptide,Calcitonin Gene Related Peptide,Calcitonin Gene Related Peptide I,Calcitonin Gene Related Peptide II,Gene-Related Peptide, Calcitonin,alpha Calcitonin Gene Related Peptide,beta Calcitonin Gene Related Peptide