King C T, Garcea M, Spector A C
Department of Psychology, Stetson University, DeLand, Florida 32720, USA.
J Neurosci. 2000 Nov 15;20(22):8426-34. doi: 10.1523/JNEUROSCI.20-22-08426.2000.
The peripheral, central, and behavioral consequences of glossopharyngeal nerve transection (GLX), regeneration, and the prevention of regeneration on the quinine-elicited responses of adult rats were concurrently examined. Oromotor taste reactivity (TR) was videotaped during intraoral infusion of 7 ml of either quinine (3 mm) or distilled water at 17, 52, or 94 d after surgery. We confirmed previous findings by showing that 17 d after neurotomy, (1) the number of circumvallate (CV) and foliate taste buds, (2) gapes (a characteristic aversive TR response), and (3) the number of Fos-like immunoreactive (FLI) neurons in the gustatory NST (gNST), particularly in the medial portion (subfield 5) of the rostral central subdivision (RC), were all severely attenuated in GLX rats. We extended these findings by showing that these lesion-induced effects were enduring when the GL did not regenerate (up to 94 d). In contrast, when the GL regenerated, as few as 52 d were sufficient to re-establish quinine-elicited TR, especially gaping, and FLI expression in RC, particularly within subfield 5, to values comparable with quinine-stimulated sham-operated rats. Evidently, the gNST maintains its potential to restore accurately the organization of neural activity that is disrupted by nerve injury, as assessed by FLI, ultimately leading to the return of normal protective oromotor responses, provided the nerve regenerates. This recovery was complete despite the reappearance of a reduced population of CV taste buds ( approximately 75% control values) and may relate to peripheral and/or central changes that occur in tandem with regeneration of the GL.
我们同时研究了舌咽神经切断术（GLX）、再生以及阻止再生对成年大鼠奎宁诱发反应的外周、中枢和行为后果。在手术后第17、52或94天，在口腔内注入7毫升奎宁（3毫米）或蒸馏水时，对口腔运动味觉反应性（TR）进行录像。我们通过以下方式证实了先前的研究结果：在神经切断术后17天，（1）轮廓乳头（CV）和叶状味蕾的数量，（2）张口动作（一种典型的厌恶TR反应），以及（3）味觉孤束核（gNST）中Fos样免疫反应性（FLI）神经元的数量，特别是在 Rostral 中央亚区（RC）内侧部分（亚区5），在GLX大鼠中均严重减弱。我们进一步扩展了这些发现，表明当舌咽神经未再生时（长达94天），这些损伤诱导的效应会持续存在。相比之下，当舌咽神经再生时，仅52天就足以重新建立奎宁诱发的TR，尤其是张口动作，以及RC中FLI的表达，特别是在亚区5内，使其值与奎宁刺激的假手术大鼠相当。显然，味觉孤束核保持着准确恢复因神经损伤而被破坏的神经活动组织的潜力，通过FLI评估，最终导致正常的保护性口腔运动反应恢复，前提是神经再生。尽管CV味蕾数量减少（约为对照值的75%）再次出现，但这种恢复是完全的，这可能与舌咽神经再生同时发生的外周和/或中枢变化有关。
