Aznar Susana, Kostova Viktorija, Christiansen Søren H, Knudsen Gitte M
Neurobiology Research Unit, Copenhagen University Hospital, 2100 Copenhagen, Denmark.
Synapse. 2005 Mar 1;55(3):196-200. doi: 10.1002/syn.20108.
The serotonergic transmitter system regulates hippocampal activity through its raphe projection to hippocampus and medial septum/diagonal band of Broca complex (MS/DBB), and most likely also indirectly through its interaction with the cholinergic neurotransmitter system. Nicotine, e.g., enhances hippocampal serotonin release probably through presynaptic nicotinic receptors. We investigated the possible presence of the alpha 7-nicotinic subunit on serotonergic neurons projecting to hippocampus and MS/DBB. By retrograde neuronal tracing, hippocampal serotonergic neurons were identified and with double fluorescence immunostaining and Alexa-488 bound alpha-bungarotoxin the presence of active alpha 7 receptor on their soma was determined. Most of the retrogradely labeled serotonin neurons contained the alpha 7 subunit. A low degree of colocalization between alpha-bungarotoxin and serotonin-positive neurons suggest that the alpha 7 subunit may be transported anterogradely to the serotonergic axonal terminals.
血清素能递质系统通过其从中缝向海马和内侧隔/布罗卡斜角带复合体（MS/DBB）的投射来调节海马活动，并且很可能还通过其与胆碱能神经递质系统的相互作用间接调节。例如，尼古丁可能通过突触前烟碱受体增强海马中血清素的释放。我们研究了投射到海马和MS/DBB的血清素能神经元上可能存在的α7烟碱亚基。通过逆行神经元追踪，识别出海马血清素能神经元，并通过双重荧光免疫染色和与Alexa-488结合的α-银环蛇毒素确定其胞体上活性α7受体的存在。大多数逆行标记的血清素神经元含有α7亚基。α-银环蛇毒素与血清素阳性神经元之间的共定位程度较低，表明α7亚基可能被顺行转运到血清素能轴突终末。
