Abstract:
Although salivation is essential during eating behavior, little is known about the brainstem centers that directly control the salivary glands. With regard to the inferior salivatory nucleus (ISN), the site of origin of the parasympathetic preganglionic cell bodies that innervate the parotid glands, previous anatomical studies have located it within the rostrodorsal medullary reticular formation. However, to date there is no functional data that shows the secretory nature of the somas grouped in this region. To activate only the somas and rule out the activation of the efferent fibers from and the afferent fibers to the ISN, in exp. 1, NMDA neurotoxin was administered to the rostrodorsal medullary region and the secretion of saliva was recorded during the following hour. Results showed an increased secretion of parotid saliva but a total absence of submandibular-sublingual secretion. In exp. 2, results showed that the hypersecretion of parotid saliva after NMDA microinjection was completely blocked by the administration of atropine (a cholinergic blocker) but not after administration of dihydroergotamine plus propranolol (α and β-adrenergic blockers, respectively). These findings suggest that the somata of the rostrodorsal medulla are secretory in nature, controlling parotid secretion via a cholinergic pathway. The data thus functionally supports the idea that these cells constitute the ISN.
摘要:
虽然在饮食行为过程中流涎是必不可少的,对直接控制唾液腺的脑干中枢知之甚少。关于下唾液核(ISN),支配腮腺的副交感神经节前细胞体的起源部位,先前的解剖学研究已将其定位在延髓网状形成内。然而,迄今为止,没有功能数据显示该区域中分组的体细胞的分泌性质。为了仅激活躯体,并排除来自ISN的传出纤维和传入纤维的激活,在exp。在图1中,将NMDA神经毒素施用到延髓区,并在随后的小时内记录唾液的分泌。结果显示腮腺唾液分泌增加,但完全没有颌下舌下分泌。在exp中。2,结果表明,通过给予阿托品(一种胆碱能阻滞剂),NMDA显微注射后腮腺唾液的高分泌被完全阻断,但在给予二氢麦角胺+普萘洛尔(α和β-肾上腺素能阻滞剂,分别)。这些发现表明,延髓的躯体本质上是分泌的,通过胆碱能途径控制腮腺分泌。因此,数据在功能上支持这些小区构成ISN的想法。