Biomaterial Database

Indoleamine-mediated reciprocal modulation of on-centre and off-centre ganglion cell activity in the retina of the cat. 1984

P Thier, and H Wässle

The effects of applying the indoleamines serotonin (5-hydroxytryptamine) and 5-methoxy-N,N-dimethyltryptamine (MDT) ionophoretically onto cat retinal ganglion cells were studied in the optically intact eye of the cat. Serotonin suppressed both the spontaneous activity and light-evoked discharge of on-centre ganglion cells, regardless of the visual stimulus used; on the other hand, it enhanced the activity of off-centre ganglion cells. MDT produced the opposite effects, i.e. it enhanced the activity of on-centre ganglion cells but suppressed that of off-centre ganglion cells. Much of the effect of serotonin on light-evoked discharge can be attributed to an alteration of maintained discharge. There was no major difference in the way brisk-sustained (X) and brisk-transient (Y) cells responded to the application of serotonin and MDT, although the effects of the indoleamines on brisk-transient (Y) cells were generally weaker than on brisk-sustained (X) cells. In view of the fact that the action of serotonin is similar to the action of a gain control system, a possible contribution of indoleamine-accumulating neurones to gain control in the cat retina is discussed.

UI	MeSH Term	Description	Entries
D008027	Light	That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.	Light, Visible,Photoradiation,Radiation, Visible,Visible Radiation,Photoradiations,Radiations, Visible,Visible Light,Visible Radiations
D008732	Methoxydimethyltryptamines	Compounds that contain the biogenic monoamine tryptamine and are substituted with one methoxy group and two methyl groups. Members of this group include several potent serotonergic hallucinogens found in several unrelated plants, skins of certain toads, and in mammalian brains. They are possibly involved in the etiology of schizophrenia.	Methylbufotenin,5-Methoxy-N,N-Dimethyltryptamine,Methoxydimethyltryptamine,N,N-Dimethyl-5-Methoxytryptamine,5 Methoxy N,N Dimethyltryptamine,N,N Dimethyl 5 Methoxytryptamine
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
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
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
D012165	Retinal Ganglion Cells	Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.	Cell, Retinal Ganglion,Cells, Retinal Ganglion,Ganglion Cell, Retinal,Ganglion Cells, Retinal,Retinal Ganglion Cell
D012701	Serotonin	A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.	5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor