Suneja S K, Potashner S J, Benson C G
Department of Anatomy, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA.
Exp Neurol. 1998 Jun;151(2):273-88. doi: 10.1006/exnr.1998.6812.
[i] In young adult guinea pigs, the effects of unilateral ossicle removal and unilateral cochlear ablation were determined on [14C]glycine or [14C]GABA release and uptake measured in subdivisions of the cochlear nucleus (CN), the superior olivary complex, and the auditory midbrain, after 2 or 5, 59, and 145 postlesion days. Activities were compared to those of age-matched, unlesioned controls. [ii] [14C]Glycine release declined bilaterally in the anteroventral and dorsal CN after ossicle removal and in the dorsal CN after cochlear ablation. [iii] Transient elevations of release occurred at 59 days in the ipsilateral posteroventral CN ([14C]glycine) and bilaterally in the ventral nucleus of the lateral lemniscus ([14C]GABA) after ossicle removal, and bilaterally in the medial superior olive ([14C]glycine) after cochlear ablation. [iv] In the medial nucleus of the trapezoid body, [14C]GABA release was depressed bilaterally 5 days after ossicle removal, but was elevated at 145 days contralaterally after ossicle removal and ipsilaterally after cochlear ablation. [v] In the contralateral central nucleus of the inferior colliculus, [14C]GABA release was elevated persistently after ossicle removal. After cochlear ablation, release was elevated at 5 days, near the control at 59 days, and elevated again at 145 days. [vi] After both lesions, [14C]glycine uptake was elevated bilaterally in the CN and medial superior olive. [14C]GABA uptake became depressed by 59 or 145 days bilaterally in the auditory midbrain. [vii] These changes may stem from regulation and may contribute to mechanisms that generate symptoms such as loudness recruitment and tinnitus, which often accompany hearing loss.
[i] 在年轻成年豚鼠中，测定了单侧听小骨切除和单侧耳蜗损毁对在损伤后2天、5天、59天和145天，耳蜗核（CN）、上橄榄复合体及听觉中脑各亚区中[¹⁴C]甘氨酸或[¹⁴C]γ-氨基丁酸（GABA）释放及摄取的影响。将这些活性与年龄匹配的未损伤对照的活性进行比较。[ii] 听小骨切除后，前腹侧和背侧CN中的[¹⁴C]甘氨酸释放双侧下降，耳蜗损毁后背侧CN中的[¹⁴C]甘氨酸释放下降。[iii] 听小骨切除后，同侧后腹侧CN中（[¹⁴C]甘氨酸）以及双侧外侧丘系腹侧核中（[¹⁴C]GABA）在59天时出现释放的短暂升高，耳蜗损毁后双侧内侧上橄榄核中（[¹⁴C]甘氨酸）在59天时出现释放的短暂升高。[iv] 在斜方体内侧核中，听小骨切除后5天[¹⁴C]GABA释放双侧降低，但听小骨切除后145天对侧及耳蜗损毁后同侧升高。[v] 在对侧下丘中央核中，听小骨切除后[¹⁴C]GABA释放持续升高。耳蜗损毁后，5天时释放升高，59天时接近对照水平，145天时再次升高。[vi] 两种损伤后，CN和内侧上橄榄核中[¹⁴C]甘氨酸摄取双侧升高。听觉中脑双侧[¹⁴C]GABA摄取在59天或145天时降低。[vii] 这些变化可能源于调节作用，并可能促成产生诸如响度重振和耳鸣等症状的机制，而这些症状常伴随听力损失出现。
