The effects of histamine on rat and monkey retinal ganglion cells
Mammalian retinas receive input from the posterior hypothalamus, and the neurotransmitter in this pathway is histamine. To determine whether histamine influences ganglion cells, we analyzed the effects of histamine on their maintained and light-evoked activity in vitro. In monkeys, histamine increas...
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Published in | Visual neuroscience Vol. 21; no. 6; pp. 935 - 943 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
New York, USA
Cambridge University Press
01.11.2004
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Subjects | |
Online Access | Get full text |
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Summary: | Mammalian retinas receive input from the posterior hypothalamus, and
the neurotransmitter in this pathway is histamine. To determine whether
histamine influences ganglion cells, we analyzed the effects of
histamine on their maintained and light-evoked activity in
vitro. In monkeys, histamine increased the maintained firing rate
in 42% of ganglion cells, decreased it in 38%, and had no effect in
20%. When histamine and the HR3 agonist, methylhistamine, were applied
to the same cells in succession, their effects were sometimes
different, a finding suggesting that at least one other histamine
receptor is present. In addition, the responses of some ganglion cells
to full-field light stimuli were decreased by histamine and
methylhistamine. In rats, the effects of histamine were somewhat
different. Histamine increased the maintained firing rate of 82% of
ganglion cells. Methylhistamine and the HR2 agonist, dimaprit, had the
same effects as histamine. In some cells, histamine increased the light
responses, but in others it decreased them. Histamine had no effect on
ganglion cells in either species when synaptic transmission was blocked
by low Ca2+/high Mg2+ Ames medium. Thus, the
major effects of histamine were on the maintained activity of retinal
ganglion cells. In both rats and monkeys, 80% or more of the ganglion
cells were affected by histamine, and these responses were mediated by
at least two of the histamine receptor subtypes. |
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Bibliography: | PMID:15733348 ark:/67375/6GQ-J1XVJ8G7-8 PII:S0952523804216133 istex:941DEA37BCBFF306DD9381A580AF83D934B470A9 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0952-5238 1469-8714 |
DOI: | 10.1017/S0952523804216133 |