SELECTIVE PHOTOTOXIC DESTRUCTION OF RAT MERKEL CELLS ABOLISHES RESPONSES OF SLOWLY ADAPTING TYPE-I MECHANORECEPTOR UNITS
SELECTIVE PHOTOTOXIC DESTRUCTION OF RAT MERKEL CELLS ABOLISHES RESPONSES OF SLOWLY ADAPTING TYPE-I MECHANORECEPTOR UNITS
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DOI：
10.1113/jphysiol.1994.sp020292
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发表时间：
1994-09-01
影响因子：
5.5
通讯作者：
OGAWA, H
中科院分区：
文献类型：
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作者：
IKEDA, I;YAMASHITA, Y;OGAWA, H
1.方法：1.将荧光染料奎纳克林（quinacrine）注入大鼠触丘默克尔细胞，观察激发光照射对支配触丘的慢适应（SA）I型单位机械反应的影响.组织学检查显示，照射10分钟后，变性特异性地定位于载有奎纳克林的默克尔细胞。即使在治疗后，与默克尔细胞相关的神经末梢也保持完整。3.在XA I型单位中，用奎纳克林激发光通过"B“滤光片（”B“光）照射圆顶后，对标准刺激（100 ms斜坡，随后是400 μ m恒定位移的2.9 s平台）的反应显著降低。照射5分钟后，反应降低至52 +/- 7%（n = 10，平均值+/- S.E.M.）预处理值的17 +/- 4%，处理10分钟，在20分钟内几乎消失。在未加载默克尔细胞的SA I型单位中，5分钟照射的反应增加到119 +/- 8%（n = 13），10分钟处理的反应增加到99 +/- 9%。照射后15 min左右，反应逐渐减弱，60 min内反应消失.当反应分为阶段性（刺激开始后0-120 ms）和紧张性（120-3000 ms）成分时，在加载奎纳克林的SA I型单位中，“紧张性”反应比“阶段性”反应受到更大的影响.在SB I型单位中，有奎纳克林负载的默克尔细胞在照射后刺激-反应曲线向右和向下移动，而在SA I型单位中没有观察到明显的变化.我们的观察结果是一致的假设，即默克尔细胞是负责SA I型单位的机械电转导。
1. The fluorescent dye quinacrine which accumulates in Merkel cells in touch domes was administered to rats and the effects of excitation light irradiation on the mechanical responses of slowly adapting (SA) type I units innervating the touch domes were investigated.2. Histological examination showed that after 10 min of irradiation degeneration was specifically localized to Merkel cells loaded with quinacrine. Nerve terminals associated with Merkel cells remained intact, even after treatment.3. In XA type I units, responses to standard stimulation (a 100 ms ramp followed by a 2.9 s plateau of 400 mu m constant displacement) decreased significantly after irradiation of the domes with quinacrine-excitation light through a 'B' filter ('B' light). With 5 min irradiation, the response decreased to 52 +/- 7% (n = 10, mean +/- S.E.M.) of the pretreated value, to 17 +/- 4% with a 10 min treatment and practically disappeared within 20 min.4. In SA type I units with non-loaded Merkel cells, the response increased to 119 +/- 8% (n = 13) with 5 min irradiation and was 99 +/- 9% with the 10 min treatment. At around 15 min after the onset of irradiation there was a gradual decrease and within 60 min the response disappeared.5. When responses were divided into phasic (0-120 ms after the onset of stimulation) and tonic (120-3000 ms) components,'tonic' responses were more affected than 'phasic' ones in quinacrine-loaded SA type I units.6. Stimulus-response curves shifted to the right and downwards in SB type I units with quinacrine-loaded Merkel cells after irradiation, but no significant change was seen in SA type I units without quinacrine.7. Our observations are consistent with the hypothesis that Merkel cells are responsible for mechanoelectric transduction in SA type I units.