Biomaterial Database

A simulation analysis on mechanisms of damped oscillation in retinal rod photoreceptor cells. 2003

Toshihiko Ogura, and Tomo Oki Satoh, and Shiro Usui, and Masahiro Yamada

Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan.

The different actions of two I(h) channel blockers, zatebradine (UL-FS 49) and ZD7288, on rod photoresponses were analysed by computer simulation using a newly revised ionic current model of the rod photoreceptor, based on Hodgkin-Huxley equations. The model, adjusted to fit the experimental results of amphibian rods, shows that both of the blockers enhance the light-induced membrane hyperpolarization. Our model can also predict a mechanism of a damped oscillation arising during the recovery phase appeared only in the presence of zatebradine which, unlike ZD7288, reduces both I(h) and I(Kv). We suggest that the oscillation can appear due to the alternative activation of voltage-dependent Ca(2+) current (I(Ca)) and calcium-dependent current (I(K(Ca)) and I(Cl(Ca))) when I(Kv) is blocked, with I(K(Ca)) having a stronger effect than I(Cl(Ca)).

UI	MeSH Term	Description	Entries
D011743	Pyrimidines	A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.
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
D002316	Cardiotonic Agents	Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).	Cardiac Stimulant,Cardiac Stimulants,Cardioprotective Agent,Cardioprotective Agents,Cardiotonic,Cardiotonic Agent,Cardiotonic Drug,Inotropic Agents, Positive Cardiac,Myocardial Stimulant,Myocardial Stimulants,Cardiotonic Drugs,Cardiotonics,Agent, Cardioprotective,Agent, Cardiotonic,Drug, Cardiotonic,Stimulant, Cardiac,Stimulant, Myocardial
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D001552	Benzazepines	Compounds with BENZENE fused to AZEPINES.
D017948	Retinal Rod Photoreceptor Cells	Photosensitive afferent neurons located in the peripheral retina, with their density increases radially away from the FOVEA CENTRALIS. Being much more sensitive to light than the RETINAL CONE CELLS, the rod cells are responsible for twilight vision (at scotopic intensities) as well as peripheral vision, but provide no color discrimination.	Photoreceptors, Rod,Retinal Rod Cells,Rod Photoreceptors,Rods (Retina),Retinal Rod,Retinal Rod Cell,Retinal Rod Photoreceptor,Retinal Rod Photoreceptors,Rod Photoreceptor Cells,Cell, Retinal Rod,Cell, Rod Photoreceptor,Cells, Retinal Rod,Cells, Rod Photoreceptor,Photoreceptor Cell, Rod,Photoreceptor Cells, Rod,Photoreceptor, Retinal Rod,Photoreceptor, Rod,Photoreceptors, Retinal Rod,Retinal Rods,Rod (Retina),Rod Cell, Retinal,Rod Cells, Retinal,Rod Photoreceptor,Rod Photoreceptor Cell,Rod Photoreceptor, Retinal,Rod Photoreceptors, Retinal,Rod, Retinal,Rods, Retinal