Amino acids — Putative afferent transmitter in the cochlea?
Amino acids — Putative afferent transmitter in the cochlea?
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氨基酸——耳蜗中假定的传入递质？
DOI：
10.1007/bf00237865
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发表时间：
1977
影响因子：
2
通讯作者：
W. Oertel
中科院分区：
文献类型：
--
作者：
R. Klinke;W. Oertel
许多物质已被证明不太可能是耳蜗的传入递质：例如乙酰胆碱，它可能是传出递质。（参见Klinke和Galley，1974年的综述），（Klinke和Evans，1977年），GABA（Bobbin和Guth，1970年; Tachibana和Kuriyama，1974年; Bobbin和Gondra，1975年; Klinke和Oertel，1975年; Fex和Wenthold，1976年; Klinke和Oertel，1977 a）和5-HT（Klinke和Oertel，1977 b）。一些其他的氨基酸还有待研究。本文研究了L-谷氨酸和L-天冬氨酸对耳蜗传入突触传递的影响。对于这两种物质，都没有有效的拮抗剂（Altmann等人，1976年）。此外，还使用了甘氨酸和GABA。实验原理和方法与前一篇论文相同（Klinke和Oertel，1977 b;另见Klinke和Evans，1977）。使用了六只猫，研究了两只耳朵。L-谷氨酸（10 ~（-3）M和2.5 ~（-10）~（-3）M）滴注14 min，对耳蜗微音电位（CM）和听神经复合动作电位（CAP）均无影响。10- 2 M时，CAP迅速降低至近50%（见图1）。这种降低在CSF冲洗后7分钟内可逆。CM保持不变。随后滴注KCN（10- 3 M）使CAP降至相同水平（见图1）。在相同条件下，L-天冬氨酸（10- 3 M），滴注14分钟，对CM或CAP没有影响。使用10- 2 M时，CAP降低近50%，用CSF冲洗7分钟后效果逆转。CM没有改变。KCN也能使CAP降至相同水平，甘氨酸达3 × 10 ~（-2）M，滴注11 min，CM和CAP均无变化。GABA高达10 ~（-2）M时，在13 min内对CM和CAP无影响。在用甘氨酸和GABA的实验期间，刺激耳蜗传出神经（参见Galley等人，1973年的技术），导致CM的增加和CAP的减少。无论是甘氨酸，也不GABA影响传出突触的功能，浓度高达10- 2 M。
A number of substances have been shown unlikely to be the afferent transmitter in the cochlea: for example acetylcholine which may be the efferent transmitter (see Klinke and Galley, 1974 for review), catecholamines (Klinke and Evans, 1977), GABA (Bobbin and Guth, 1970; Tachibana and Kuriyama, 1974; Bobbin and Gondra, 1975; Klinke and Oertel, 1975; Fex and Wenthold, 1976; Klinke and Oertel, 1977a) and 5-HT (Klinke and Oertel, 1977b). Some other amino acids have yet to be investigated. In the present paper the effects of L-glutamate and L-aspartate were tested on the afferent synaptic transmission in the cochlea. For both substances potent antagonists are not available (Altmann et al., 1976). Additionally glycine and GABA were used. The principle of experiments and the methods were identical to the preceding paper (Klinke and Oertel, 1977b; see also Klinke and Evans, 1977). Six cats were used, both ears were studied. L-glutamate (10-3M and 2.5-10-3M), instilled for 14 min, did not influence the cochlear microphonic (CM) or the compound action potential (CAP) of the auditory nerve. With 10-2M the CAP was promptly reduced to nearly 50%(see Fig. 1). This decrease was reversible within 7 min of flushing with CSF. The CM remained unchanged. Subsequent instillation of KCN (10-3M) reduced the CAP to the same level (see Fig. 1). Under identical conditions, L-aspartate (10-3M), instilled for 14 min, had no effect on the CM or the CAP. With 10-2M the CAP was reduced nearly to 50%, the effect reversing after 7 min flushing with CSF. The CM was not altered. KCN also reduced the CAP to the same level.Glycine up to 3" 10-2M, instilled for as long as 11 min, caused no change of the CM or the CAP. GABA up to 10-2M had no effect upon the CM and the CAP within 13 min of instillation. During the experiments with glycine and GABA cochlear efferents were stimulated (see Galley et al., 1973 for technique), leading to an increase of the CM and a decrease of the CAP. Neither glycine nor GABA influenced the function of the efferent synapses in concentrations as high as 10-2M.