Dostrovsky J O, Hu J W, Sessle B J, Sumino R
Brain Res. 1982 Dec 9;252(2):287-97. doi: 10.1016/0006-8993(82)90396-1.
Electrode penetrations were made in the mesencephalon and caudal brainstem at the levels of the periaqueductal gray matter (PAG) and nucleus raphe magnus (NRM) in chloralose-anaesthetized or decerebrate cats. In a systematic fashion, mesencephalic and brainstem loci at every 1 mm of vertical depth were electrically stimulated in a series of mediolateral or anteroposterior electrode penetrations to determine the lowest stimulation threshold at each locus for suppressing the digastric jaw-opening reflex evoked by tooth pulp or infraorbital nerve stimulation; at some loci, the threshold current required for suppressing infraorbital nerve-evoked neck reflexes was also determined. Stimulation at sites within large regions of the mesencephalon and caudal brainstem was effective in suppressing these reflexes at less than 4 X the lowest threshold for reflex suppression in each animal. However, in these regions the areas of lowest threshold in the mesencephalon generally corresponded to the ventrolateral PAG and adjacent nucleus cuneiformis and part of the lateral reticular formation (LRF) and in the caudal brainstem they corresponded to NRM and the adjacent nuclei reticularis magnocellularis (RMC) and gigantocellularis (RGC). These findings suggest that there may be mesencephalic and caudal brainstem areas in addition to PAG and NRM that are equally effective in modulating reflex activity.
在水合氯醛麻醉或去大脑的猫中，在中脑和延髓脑干的导水管周围灰质（PAG）和中缝大核（NRM）水平进行电极穿刺。以系统的方式，在一系列中外侧或前后电极穿刺中，对垂直深度每1毫米处的中脑和脑干位点进行电刺激，以确定每个位点抑制牙髓或眶下神经刺激诱发的二腹肌下颌张开反射的最低刺激阈值；在一些位点，还确定了抑制眶下神经诱发的颈部反射所需的阈值电流。在中脑和延髓脑干的大片区域内的位点进行刺激，在低于每只动物反射抑制最低阈值4倍的情况下，对抑制这些反射有效。然而，在这些区域中，中脑最低阈值区域通常对应于腹外侧PAG和相邻的楔形核以及部分外侧网状结构（LRF），在延髓脑干中，它们对应于NRM和相邻的巨细胞网状核（RMC）和大细胞网状核（RGC）。这些发现表明，除了PAG和NRM之外，可能还有中脑和延髓脑干区域在调节反射活动方面同样有效。
