Serotonin released from amacrine neurons is scavenged and degraded in bipolar neurons in the retina.
Serotonin released from amacrine neurons is scavenged and degraded in bipolar neurons in the retina.
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DOI：
10.1111/j.1471-4159.2009.06270.x
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发表时间：
2009-10
影响因子：
4.7
通讯作者：
Fischer AJ
中科院分区：
文献类型：
--
作者：
Ghai K;Zelinka C;Fischer AJ
神经递质血清素在视网膜中由一种无长突神经元合成，但在许多脊椎动物的双极神经元中积累。双极细胞中血清素的机制、功能和目的仍然未知。在这里，我们证明外源性血清素在一种不同类型的双极神经元中短暂积累。 KCl 介导的去极化导致无长突神经元的血清素消耗，随后，血清素被双极神经元吸收。双极神经元内源性或外源性血清素的积累被选择性再摄取抑制剂阻断。即使合成血清素的无长突神经元被破坏，外源性血清素也会被双极神经元特异性吸收。排除血清素通过间隙连接从无长突扩散到双极神经元的可能性。此外，抑制单胺氧化酶 (A) 可防止双极神经元中血清素的降解，表明这些神经元中存在 MAO(A)。然而，囊泡单胺转运蛋白（VMAT2）仅存在于无长突细胞中，这表明血清素不会被转运到突触囊泡中并被重新用作双极神经元中的递质。我们得出的结论是，积累血清素的双极神经元通过主动运输和降解邻近无长突细胞合成的血清素来执行视网膜中的神经胶质功能。
The neurotransmitter serotonin is synthesized in the retina by one type of amacrine neuron but accumulates in bipolar neurons in many vertebrates. The mechanisms, functions and purpose underlying of serotonin in bipolar cells remain unknown. Here, we demonstrate that exogenous serotonin transiently accumulates in a distinct type of bipolar neuron. KCl-mediated depolarization causes the depletion of serotonin from amacrine neurons and, subsequently, serotonin is taken-up by bipolar neurons. The accumulation of endogenous or exogenous serotonin by bipolar neurons is blocked by selective reuptake inhibitors. Exogenous serotonin is specifically taken-up by bipolar neurons even when serotonin-synthesizing amacrine neurons are destroyed; excluding the possibility that serotonin diffuses through gap junctions from amacrine into bipolar neurons. Further, inhibition of monoamine oxidase (A) prevents the degradation of serotonin in bipolar neurons, suggesting that MAO(A) is present in these neurons. However, the vesicular monoamine transporter (VMAT2) is present only in amacrine cells suggesting that serotonin is not transported into synaptic vesicles and re-used as a transmitter in the bipolar neurons. We conclude that the serotonin-accumulating bipolar neurons perform glial functions in the retina by actively transporting and degrading serotonin that is synthesized in neighboring amacrine cells.
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影响因子：
2.5
作者：
Fischer, Andy J.;Stanke, Jennifer J.;Omar, Ghezal
通讯作者：
Omar, Ghezal
DOI：
10.1016/s0736-5748(97)00026-9
发表时间：
1997-10-01
影响因子：
1.8
作者：
Rios, H;Brusco, A;Saavedra, JP
通讯作者：
Saavedra, JP
影响因子：
4.1
作者：
COTTON, RGH;MCADAM, W;MORGAN, FJ
通讯作者：
MORGAN, FJ
影响因子：
2.5
作者：
Fischer, AJ;Skorupa, D;Walton, NA
通讯作者：
Walton, NA
DOI：
10.1007/bf02284829
发表时间：
1996-11-01
期刊：
JOURNAL OF NEUROCYTOLOGY
影响因子：
--
作者：
Schlemermeyer, E;Chappell, RL
通讯作者：
Chappell, RL