Depletion of striatal β-phenylethylamine following dopamine but not 5-HT denervation

The effects of lesions of the substantia nigra (electrolytic 2 mA 10 sec, or 6-OHDA 2 or 8 micrograms) and of the midbrain raphé nuclei (electrolytic 2 X 1.0 mA 10 sec) at 7 days postlesion on striatal levels of beta-phenylethylamine, DA, DOPAC, HVA, 5-HT and 5-HIAA and on hypothalamic levels of beta-phenylethylamine, DA, NA, 5-HT and 5-HIAA were investigated. In the presence of deprenyl (2 mg kg-1 2 hr SC), both electrolytic and 6-OHDA-induced dopamine-depleting lesions of the nigra but not 5-HT-depleting lesions of the raphé nuclei resulted in a marked decrease in the accumulation of beta-phenylethylamine. The marked reduction in accumulation of striatal beta-phenylethylamine in response to lesions of the substantia nigra indicates that the intraneuronal compartment is a major site of striatal beta-phenylethylamine synthesis. An equivalent decrease (approximately 40%) in the accumulation of 5-HT was observed following electrolytic lesions of the substantia nigra or raphé nuclei after administration of L-5-HTP (200 mg kg-1 hr IP). As L-5-HTP at the dose employed in this study is taken up non-selectively by both DA- and 5-HT-containing neurones the loss of L-AAD following nigral and raphé lesions was apparently equivalent. These results indicate that depletion of beta-phenylethylamine may not be simply attributable to a general loss of L-AAD following lesions of monoamine-containing neurones and suggest either co-localisation of beta-phenylethylamine and DA or the existence of distinct beta-phenylethylamine-containing neurones.     

Cortical topography of thalamic intralaminar nuclei

The coritical projection of the thalamic intralaminar nuclei (ILN) has been studied by injecting little amounts of horseradish peroxidase (HRP) on the cerebral cortex of the rat. All of the cortical areas (except area 17) receive ipsilateral projections from at least one nucleus of the ILN. The nucleus centralis had the largest number of labeled neurons, principally after injections in frontal, temporal and occipital cortical areas. The nucleus paracentralis presented only moderate numbers of HRP positive neuronrs from the frontal cortex, and very few from parietal and temporal areas. The nucleus parafascicularis showed labeled somata after frontal injections as well as parietal and temporal areas. In comparison to the other ILN, the amount of labeled neurons in this nucleus is relatively small. The nucleus centralis medialis presented the least number of labeled neurons regardless of injected area. Its cortical efferents remain restricted to small areas of the dorsal aspects of frontal, anterior cingular and temporal cortices. Each of the ILN contains neurons which connect with more than one cortical zone, according to a characteristics topographic distribution.     

The laminar distribution of intracortical fibers originating in the olfactory cortex of the rat

In this study, the autoradiographic method for tracing axonal connections was used to identify the laminar distribution of intracortical fibers originating in the olfactory cortical areas of the rat. Most of the projections can be divided into two major fiber systems with different laminar patterns of termination. The first of these, termed the layer Ib fiber system, arises in the anterior olfactory nucleus, the anterior and posterior piriform cortex, and the lateral entorhinal cortex, and terminates predominantly in layer Ib and, in many cases, layer III of the entire olfactory cortex. The second system, termed the layer II-deep Ib fiber system, originates in three relatively small olfactory cortical areas-the dorsal peduncular cortex, the ventral tenia tecta, and the periamygdaloid cortex and terminates in and around the cells of layer II in most parts of the olfactory cortex. There is significant overlap in the laminar distribution of the two systems, although the distinction between them is readily apparent. Within the layer Ib fiber system there are relatively slight but consistent differences in the lamination of fibers from different areas. The fibers from the anterior olfactory nucleus are concentrated in the deep part of layer Ib while those from the anterior piriform cortex are concentrated in the superficial part of this layer. The fibers from the posterior piriform cortex tend to be densest in the middle of layer Ib. These differences are maintained in all areas of termination of each set of fibers, both ipsilaterally and contra-laterally. In addition, intracortical fibers from the anterior cortical nucleus of the amygdala are distributed throughout layer I, including layer la and Ib. Fibers from the nucleus of the lateral olfactory tract terminate bilaterally around the cells of the islands of Callej a and the medial edge of the anterior piriform cortex.     

大鼠外侧隔核微量注射精氨加压素的心血管作用及机理探讨

实验在乌拉坦麻醉大鼠上进行。观察了微量精氨加压素在外侧隔核的心血和作用，并从中枢和外周两方面探讨了其作用机理。结果发现：１．外侧隔核注射精氨加压素，使平均动脉压和心率明显升高。２．在侧脑室注射钠洛酮，使上述心血管效应降至１．２±０．１ｋＰａ和２０．５±２．０次／ｍｉｎ。在延髓头端腹外侧注射普鲁卡因。３．静脉注射心得安，使上述升压效应降至１．７±０．８ｋＰａ，加快心率作用不再出现。     

The Projections of the Lateral Reticular Nucleus to the Deep Cerebellar Nuclei. An Experimental Analysis in the Rat

The projections of the lateral reticular nucleus (LRN) to the cerebellar nuclei were studied using the retrograde axonal transport of tetramethyl rhodamine dextran amine (10% solution in 0.01 M neutral phosphate buffer) in 19 adult Wistar strain rats. The cerebellar nuclei receive topographically organized projections from the LRN. The projections are bilateral with an ipsilateral predominance and they are symmetrical. The contralateral component is progressively larger for projections to the nuclei interpositalis, to the nucleus lateralis and to the nucleus medialis. The projections to the various cerebellar nuclei arise from rostrocaudally oriented columns of neurons located in different (partly overlapping) areas of the magnocellular division of the LRN. The nucleus lateralis receives terminals from the dorsomedial area (mainly from the rostral level of the LRN), the nuclei interpositalis from the dorsolateral area (mainly from the central level) and the nucleus medialis from the intermedioventral area (mainly from the caudal level). Afferent fibres from the small subtrigeminal division were traced to the three cerebellar nuclei and from the parvocellular division to the nuclei interpositalis and medialis. The density of the projections from the LRN to the nuclei interpositalis increases progressively with the shift of the terminal field from the rostrolateral to the caudomedial part of the nucleus. The projections to the nucleus lateralis reach principally the dorsolateral hump, whereas only a few neurons project to the other divisions (parvo- and magnocellular). The projections to the various regions of the nucleus medialis show different densities. The highest density was found for projections to the caudal part, in particular to the dorsolateral protuberance and to the ventrolateral area of the middle division. Conversely, a low density of projections was found for the other areas of the middle division. The regions of the magnocellular division of the LRN which project to the nuclei lateralis (and are thus related to the cerebral cortex), interpositalis (related to the red nucleus) and medialis (related to the spinal cord) also receive afferent terminals from the cerebral cortex, the red nucleus and the spinal cord respectively, in addition to various afferent inputs. Thus, each of these areas is apparently concerned with integrating some spinal and supraspinal information in reverberating circuits.     

Effects of Timed Melatonin Infusions and Lesions of the Suprachiasmatic Nuclei on Prolactin and Progesterone Secretions in Pregnant or Pseudopregnant Mink (Mustela vison)

To test the hypothesis that the duration of melatonin secretion may be a critical parameter in the transduction of photoperiodic signals on prolactin and progesterone secretions, timed intravenous melatonin infusions were carried out in intact and ganglionectomized pregnant and pseudopregnant mink. To localize the target sites of melatonin, electrolytic lesions of hypothalamic nuclei were performed in females receiving melatonin infusions. As a control, the first experiment was designed to confirm that pineal denervation by bilateral ablation of the superior cervical ganglion rendered the pregnant mink totally unresponsive to the inhibitory effects of short days on progesterone secretion. In the following experiments, timed intravenous melatonin infusions were carried out in intact and ganglionectomized females from Day 12 to 32 of pregnancy or pseudopregnancy. Daily infusions of melatonin for 16 h in intact females or for 11 or 13 h in ganglionectomized females suppressed the rise in plasma prolactin and progesterone levels. In intact as in ganglionectomized females, daily infusions of melatonin for 9 h delayed the rise in plasma prolactin concentrations without affecting the secretion of progesterone. In ganglionectomized females, saline infusions for 13 h or melatonin infusions for 7h did not modify the secretions of prolactin and progesterone. In ganglionectomized females bearing lesions of the Suprachiasmatic nuclei or the retrochiasmatic area, melatonin infusions for 13 h were still able to inhibit prolactin and progesterone secretions. These results are consistent with the hypothesis postulating that the peak duration of melatonin secretion is a critical parameter for transducing photoperiodic responses in pregnant or pseudopregnant mink. Secondly, they suggest that the Suprachiasmatic nuclei and the retrochiasmatic area are not essential for the action of melatonin in the photoperiodic control of prolactin and progesterone secretions during pregnancy or pseudopregnancy in the mink.     

Expression of cholecystokinin and somatostatin genes in the human thalamus.

The cholecystokinin (CCK) gene is expressed in thalamocortical and thalamo-striatal neurons of the rat. In the cat, this peptide is found in some intralaminar and midline nuclei, whereas somatostatin (SRIF) is expressed in the reticular nucleus of the cat but not in rat. Since the putative neurotransmitters used by thalamic neurons are still incompletely known, especially in humans, we investigated the expression of the CCK and SRIF genes in the human thalamus by using hybridization histochemistry. CCK mRNA was found in many neurons, located in several nuclei of the dorsal thalamus. They were especially numerous and widespread in the nuclei associated with the internal thalamic lamina. They formed a continuum in the basal medial thalamus, from the central-medial nucleus, through the centre median/parafascicular complex to the limitans and suprageniculate nuclei. In addition, neurons with CCK mRNA were found medially and laterally to the mediodorsal nucleus, in the midline and intralaminar nuclei. Only rare neurons with CCK mRNA were found in other nuclei (e.g., in the ventral group of nuclei). SRIF mRNA was found in many neurons of the reticular nucleus, but not in the dorsal thalamus. Neurochemical features of the human thalamus, for the genes studied here, resemble those found in the cat. SRIF may play a role in modulating dorsal thalamic impulses, which may be conveyed through CCK innervation to the striatum and, partly, to the cortex.     

Fertilization and early embryology: Human blastocyst grading: an indicator of developmental potential?

We have observed marked variation in the in-vitro developmentof individual human embryos to the blastocyst stage which waspoorly associated with the grade of the embryo on the day oftransfer (day 2). Therefore we also graded embryos at the blastocyststage to determine if their development potential can be betterpredicted at this stage. A total of 41 blastocysts were categorizedinto three grades depending on their morphology. Various parameterssuch as hatching, adherence, growth and amount of human chorionicgonadotrophin (HCG) secreted were documented. The number ofnuclei in another 34 blastocysts belonging to the three gradeswere measured. Also morula stage embryos with large vacuolesbut no morphological differentiation were included in a separategroup called ‘vacuolated morulae’. Overall, therewas no significant difference between grade 1 and 2 blastocystsas assessed by their development to day 14, cumulative HCG secretionand nuclei counts. Grade 3 blastocysts reflected ‘poor’morphology, secreted significantly lower levels of HCG and hadsignificantly fewer nuclei than the other two grades. Vacuolatedmorulae did not resemble blastocysts in their morphologicaldevelopment, secreted no HCG and had significantly fewer nucleithan grade 1 and 2 blastocysts. This study illustrates the needfor selecting blastocysts for transfer to the uterus or forcryopreservation to allow a better assessment of the successof these techniques. In addition, the data will be useful forevaluating the effects of techniques such as co-culture withfeeder cells on the development of embryos to the blastocyststage and beyond.     

树鼩脑干中缝核的细胞构筑研究

用尼氏染色法，对树鼩脑干中缝核的细胞构筑进行了研究。结果表明，树鼩脑干中缝核的细胞构筑与猫、大鼠、兔等动物基本相似。在延髓有中缝隐核、中缝苍白核和中缝大核的尾端，在脑桥有中缝大核的嘴端、中缝桥核、中央上核和中缝背核的尾端，在中脑有中缝背核嘴端、中间线形核和嘴侧线形核。中缝核含有多种神经元，在胞体大小和形状方面各异。各中缝核常含有几种神经元，在结构上呈现一定特征。     

Distribution of motoneurons supplying cat sartorius and tensor fasciae latae, demonstrated by retrograde multiple-labelling methods.

Sartorius (SART) and tensor fasciae latae (TFL) in the cat hindlimb are functionally heterogeneous muscles with regions that differ in their skeletal actions and electromyographic recruitment during normal activity. The topographical organization of motoneurons supplying different regions of SART or TFL has been investigated by exposing cut nerve branches supplying different peripheral territories to a combination of retrograde tracers, including Fast Blue (FB), Fluorogold (FG), and horseradish peroxidase (HRP). Motoneurons supplying medial, central, and anterior regions of SART were intermixed extensively throughout a single columnar nucleus located in the ventrolateral part of segments L4 and L5. With this column, motoneurons supplying medial SART tended to lie more rostrally than those supplying anterior regions, but the gradient was modest and showed some cat-to-cat variation. Two major branches entered anterior SART at different proximodistal levels. When these two branches were exposed to different tracers, most motoneurons contained a single tracer; only a few double-labelled cells were apparent. The labelling suggests that anterior SART may contain two separate, in-series divisions of motor units. In TFL, motoneurons supplying nerve branches to posterior, central, and anterior parts of the muscle were intermingled indiscriminately in a single ventrolateral cell column in L6 and rostral L7. These results suggest that topographical organization in lumbar motor nuclei does not always reflect the highly ordered biomechanical and functional specialization evident in the peripheral organization of the muscles themselves.