Differential expression of vasopressin receptor binding in the hypothalamus during lactation in golden hamsters

Vasopressin (AVP) receptor binding within hypothalamic sites was compared between cycling and lactating female golden hamsters. The density of AVP receptor binding was analyzed by quantitative autoradiography within the ventrolateral hypothalamus and dorsomedial hypothalamic nucleus. Lactation was correlated with a disappearance of AVP receptor binding within the ventrolateral hypothalamus. In contrast, lactation was associated with a two- to three-fold increase in the density of AVP receptor binding within the dorsomedial hypothalamic nucleus. These results suggest that AVP receptor binding within the ventrolateral hypothalamus is responsive to gonadal hormones in female golden hamsters. However, the increase in binding observed within the dorsomedial hypothalamus may be related to other neurobiological changes associated with lactation.     

Serotonin 5- HT (2C) receptor knockout mice: autoradiographic analysis of multiple serotonin receptors.

Quantitative receptor autoradiography was used to study possible alterations of the densities of multiple serotonin (5-HT) receptor subtypes and of serotonin transporter in the brain of 5-HT(2C) receptor knockout mice. The radioligands employed were [(3)H]citalopram, [(3)H]WAY100,635, [(3)H]8-OH-DPAT, [(3)H]GR125743, [(3)H]sumatriptan, [(3)H]MDL100,907, [(125)I](+/-)DOI, [(3)H]mesulergine, [(3)H]5-HT, [(3)H]GR113808, and [(3)H]5-CT. As expected, radioligands that label 5-HT(2C) receptors showed a complete absence of labeling in mutant mice choroid plexus and significantly reduced densities in other brain regions expressing 5-HT(2C) receptors. With the rest of the radioligands, no significant alterations in the densities of labeled sites were found in any brain region. In situ hybridization showed no changes in 5-HT(2A) receptor and serotonin transporter mRNA levels, whereas 5-HT(2C) receptor mRNA levels were reduced in certain brain regions. The present results indicate that the mouse serotonergic system does not exhibit compensatory up- or down-regulation of the majority of its components (serotonin transporter and most 5-HT receptor subtypes) in response to the absence of 5-HT(2C) receptors.     

人胚呼吸道上皮细胞非时序DNA合成

为研究和比较化学致癌物对人呼吸道上皮细胞和纤维母细胞的损伤及损伤后DNA修复合成的差异,作者用直接致癌物4-硝基喹啉-1-氧化物(4-NQO)和间接致癌物3,4-苯并芘(BaP)处理人胚鼻咽、气管上皮细胞和纤维母细胞,用放射自显影术测定这3种细胞的非时序脱氧核糖核酸合成(UDS)。用4-NQO处理后,这3种细胞的UDS均呈明显的剂量依赖(dose dePendency)关系,但气管和鼻咽上皮细胞UDS平均分别是纤维母细胞的3.0和2.4倍。用BaP处理后,气管和鼻咽上皮细胞UDS呈现明显的剂量依赖关系,而纤维母细胞未见这种关系。气管和鼻咽上皮细胞的UDS平均分别是纤维母细胞的8.6和3.0倍。     

Ultrastuctural studies of the primate lateral geniculate nucleus: Morphology and spatial relationships of axon terminals arising from the retina,visual cortex (area 17), superior colliculus,parabigminal nucleus,and pretectum of Galago crassicaudatus

The electron microscopic autoradiographic tracing method has been used to examine the morphology and postsynaptic relationships of five projections (retina, cortical area 17, superior colliculus (tectal), parabigeminal nucleus, and pretectum) to the dorsal lateral geniculate nucleus of the greater bush baby galago crassicaudatus. Retinal terminals have been examined in the contralaterally innervated layer of each of the three matched pairs [parvi-(X-cell), magno- (Y--cell), and koniocellular (small, W-cell)] of geniculate layers. These terminals are large and contain pale mitochondria and round vesicles (RLPs). RLPs are presynaptic to juxtasomatic regions of parvi-and magnocellular neurons. In contrast, RLPs innervate more distal regions of konicellular neurons. Labeled cortical, tectal, and parabigeminal terminals are relatively small and contain round vesicles na dark mitochondria. Cortical terminals in each of the three representative layers are presynaptic to small diameter dendrites. No convergence of cortical and retinal terminals has been seen in any layer. Labeled tectal and parabigminal terminals are found primarily in the koniocellular layers, but the latter are also seen in all other layers. Tectal and parabigeminal terminals have been observed converging with retinal terminals on dendrites of some koniocellular neurons. Labeled pretectogeniculate terminals contain densely packed pleomorphic vesicles, dark mitochondria, and a dark cytoplasmic matric. These terminals, which are present in each of the representative layers, are presynaptic to conventional dendrites and profiles containing loosely despersed pleomorphic vesicles and a pale cytoplasmic matrix. © 1994 Wiley-Liss, Inc.     

Ontogenetic Development of 5-HT1D Receptors in Human Brain: An Autoradiographic Study

The pattern of pre- and postnatal appearance of 5-HT_1D receptors throughout the different areas of the human brain was studied by quantitative in vitro autoradiography, using [¹²⁵I]GTI (serotonin O -carboxymethyl-glycyl-[¹²⁵I]tyrosinamide) as a ligand. The anatomical distribution of 5-HT_1D receptors in neonatal, infant and children's brain was in good agreement with that observed in the adult, the basal ganglia and substantia nigra being the most intensely labelled areas. The development of these receptors throughout the human brain was mainly postnatal: low densities of [¹²⁵I]GTI binding sites were observed at the fetal/neonatal stage in most regions analyzed, in contrast with the high levels of labelling found in infant and children's brains. Indeed, in a number of regions, including the globus pallidus, substantia nigra and visual cortex, a peak of overexpression of 5-HT_1D receptors was observed in the first decade of life. Such overexpression could support a regulatory role for 5-HT_1D receptors in advanced periods of the CNS developmental process. Our results also indicate that the administration of drugs acting on 5-HT_1D receptors during the early postnatal period of life could result in modifications of their properties, as these receptors are already functional in this period.     

Sensory deafferentation fails to modify muscarinic receptor binding in raccoon somatosensory cortex

The characteristics and distribution of muscarinic acetylcholine (mACh) receptor binding in primary somatosensory (SI) cortex and the caudate nucleus of raccoons were studied using [3H]-QNB, a muscarinic antagonist. The binding characteristics were similar to reported values in rat and cat. Autoradiographs produced from tissue sections labeled with [3H]-QNB showed the distribution of mACh receptors in the forebrain of the raccoon. [3H]-QNB binding was highest in cerebral cortex, neostriatum and hippocampus. Within SI cortex, binding was high in layers I-III and VI and relatively low in layers IV and V. Autoradiographs obtained from animals that had undergone peripheral deafferentation of part of the forepaw revealed no changes in [3H]-QNB binding in the affected cortical region during the time that physiological reorganization is known to occur.     

Ultrastructural identification and localization of climbing fiber terminals in the fastigial nucleus of the cat

Following injections of 3H-leucine and 35S-methionine in the caudal half of the medial accessory olive, labeled climbing fibers were found contralateral to the injection site in the sagittal A-zone of the cerebellar vermis and in the fastigial nucleus. Labeling in the fastigial nucleus was analyzed with ultrastructural autoradiography. Labeled boutons of climbing fibers were found in the neuropil but never on somata. They contain spherical vesicles and occasionally some dense core vesicles in an electron-lucent matrix. The terminals of climbing fiber collaterals in the fastigial nucleus resemble climbing fiber terminals in the molecular layer with respect to their internal ultrastructural characteristics.     

穿透性角膜移植术后角膜内皮细胞之命运

地２组猴行５。５→５．０ｍｍ穿透性角膜移植术，异种组４只，同种组４只，术前用冷冻创伤＾３Ｈ－ＴｄＲ标记法标记受生角膜内皮细胞，术后１４周摘除眼球，用放射自显影法显示银颗粒的分布。     

Effect of long-term sucralfate ingestion on antral and fundic epithelial proliferation in the rat

Sucralfate accelerates the healing of chronic gastric ulcers, but its mechanism is not well understood. We studied the effect of long-term administration of sucralfate on gastric epithelial proliferation in the rat by means of tritiated thymidine autoradiography. Rats were treated perorally with 500 mg/kg sucralfate once a day. After 28 days, rats were injected with tritiated thymidine 1µCi/g body weight and sacrificed 1 hr later. Autoradiographs from antral and fundic mucosae were prepared and a number of proliferative measurements were made. Long-term sucralfate administration produced an increase in tritiated thymidine labeling of epithelial cells and expansion of the proliferative zone in antral mucosa. These results indicate that long-term sucralfate ingestion stimulates gastric antral epithelial proliferation in the rat. In light of the fact that chronic gastric ulcers are usually located in the antral region in humans, this enhanced epithelial proliferation may contribute to the beneficial effect of sucralfate in accelerating the healing of gastric ulcers.     

门脉高压性胃粘膜损害出血的细胞动力学

探讨肝硬变门脉高压性胃粘膜损害出血的机制。应用放射自显影技术观察肝硬变门脉高压大鼠在饥饿１２－３６ｈ后的胃粘膜上皮细胞标记指数变化及其与胃粘膜出血的关系。结果：１；ＬＣ－ＰＨＴ鼠平均ＬＩ氏于对照，出血灶局部２ＬＩ低于周围相对正常粘膜。２．随饥饿持续时间延长ＬＩ呈降低趋势，而出血率及严重程度呈增加趋势，尤以严重程度增加为著。３．当出血为０－３级时与ＬＩ呈显著负相关；为３－４级时两者间呈正相关但未达显