Loss of motoneurons in the ventral compartment of the rat hypoglossal nucleus following early postnatal exposure to alcohol.

Perinatal alcohol exposure (AE) has multiple detrimental effects on cognitive and various behavioral outcomes, but little is known about its impact on the autonomic functions. In a rat model of fetal alcohol spectrum disorders (FASD), we investigated neurochemical and neuroanatomical alterations in two brainstem nuclei, the hypoglossal nucleus (XIIn) and the dorsal nucleus of the vagus nerve (Xdn). One group of male Sprague-Dawley rats (n=6) received 2.625 g/kg ethanol intragastrically twice daily on postnatal days (PD) 4-9, a period equivalent to the third trimester of human pregnancy, and another group (n=6) was sham-intubated. On PD 18-19, the rats were perfused and medullary sections were immunohistochemically processed for choline acetyltransferase (ChAT) or two aminergic receptors that mediate excitatory drive to motoneurons, α1-adrenergic (α1-R) and serotonin 2A (5-HT(2A)-R), and c-Fos. Based on ChAT labeling, AE rats had reduced numbers of motoneurons in the ventral XIIn (XIIn-v; 35.4±1.3 motoneurons per side and section vs. 40.0±1.2, p=0.022), but not in the dorsal XIIn or Xdn. Consistent with ChAT data, both the numbers of α1-R-labeled motoneurons in the XIIn-v and the area of the XIIn-v measured using 5-HT(2A)-R staining were significantly smaller in AE rats (19.7±1.5 vs. 25.0±1.4, p=0.031 and 0.063 mm² ±0.002 vs. 0.074±0.002, p=0.002, respectively). Concurrently, both 5-HT(2A)-R and c-Fos staining tended to be higher in AE rats, suggesting an increased activation. Thus, postnatal AE causes motoneuronal loss in the XIIn-v. This may compromise upper airway control and contribute to increased risk of upper airway obstructions and sudden infant death in FASD victims.

OBSERVATION ON THE ARTERIES OF THE HUMAN MEDULLA OBLONGATA / 解剖学报

The origin, distribution, anastomoses and variations of the arteries of medulla oblongata were observed on 110 Chinese adult brains. The internal arteries and their territories were observed on 20 brains by artereography and clearing method (Spalteholz's technic). The results were as follows: The arteries of medulla oblongata could be divided into four groups according to their distribution. The arteries of the anteromedian and anterolateral groups arose from the anterior spinal artery, and also from the vertebral artery and basilar artery. The arteries of the lateral group contained a series of small arterial rami, which arose from the vertebral artery, posterior inferior cerebellar artery, anterior inferior cerebellar artery and basilar artery. The arteries of the posterior group arose from the posterior spinal artery and posterior inferior cerebellar artery. The arteries of each group branched and penetrated into the medulla, they ramify into fine branches, and the capillary network was formed. The internal anteromedian arteries supplied the hypoglossal nucleus, medial lemniseus etc. The internal anterolateral arteries supplied chiefly pyramidal tract. The internal posterior arteries supplied the gracile and cuneate nuclei. The internal lateral arteries supplied the rest of the areas which include reticular formation, dorsal nucleus of the vagus nerve etc.. The arterial supply of the medullary lateral area and the endartery were discussed.