KOCH三角的解剖

本实验解剖了110例人心标本(成人70、儿童40)的Koch三角区,观察和测量了房室结的形态、大小、毗邻和标志。房间隔及冠状窦口上、下方均有肌束连于房室结。Todaro腱在儿童多全部为腱性;在成人,其后部为肌性。三角区的深面为左、右心房壁和室间隔顶所构成的锥形间隙,其内为进入房室结区的血管和神经。根据构成不同,可将三角区分为5个区,即前上角的纤维支架区和房室结区,其余部分自上向下分别为房间隔区、右房壁区和室间隔区。本文还讨论了这些形态结构的功能及外科意义。     

Response of glucose-responsive ventromedial hypothalamic neurons to scrotal and preoptic thermal stimulation in rats

Almost all ventromedial hypothalamic (VMH) neurons facilitated by electro-osmotic application of glucose responded to scrotal thermal stimulation. On the other hand, only 50% of neurons which did not respond to glucose responded to the thermal stimulation. The VMH neurons facilitated or inhibited by scrotal warming were mostly facilitated or inhibited by preoptic warming, respectively. These results suggest that thermal signals from scrotal skin and preoptic area were conveyed to VMH neurons, especially to glucose-responsive ones, and could influence feeding control.     

Blood endotyping distinguishes the profile of vitiligo from that of other inflammatory and autoimmune skin diseases

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Ultrasonographic assessment of human skeletal muscle size

The measurement of human muscle size is essential when assessing the effects of training, disuse and ageing. The considered gold standard for cross-sectional area measurements of muscle size is magnetic resonance imaging (MRI). However, MRI is costly and often inaccessible. The aim of the present study was to test the reproducibility and validity of a more accessible alternative method using ultrasonography (ULT). We examined the cross-sectional areas in the vastus lateralis muscle of six individuals. Axial-plane ULT scans were taken at given levels along the entire muscle length. The ULT scanning was repeated on different days (reliability) and validated against MRI-based measurements. Mean intraclass correlation coefficients were 0.998 for the reliability of ULT and 0.999 for the validity of ULT against MRI. The coefficient of variation values for cross-sectional area measurements assessed by six different experimenters were 2.1% and 0.8% for images obtained with ULT and MRI, respectively. The ULT method is a valid and reliable alternative tool for assessing cross-sectional areas of large individual human muscles. The present findings justify the application of the ULT method for the detection of changes throughout large muscles in response to training, disuse or as a consequence of sarcopenia.     

Effects of carbon dioxide on preoptic thermosensitive neurons in vitro

Effects of carbon dioxide (CO₂) on the firing rates of preoptic thermosensitive neurons were examined in rat brain slice preparations. The perfusing medium was saturated with gas mixtures consisting of 90% O₂ and one of various concentrations (5%, 6.3%, 7.5%, and 10%) of CO₂ balanced with N₂. The medium containing 5% CO₂ was used as control. Most preoptic neurons were inhibited during application of a high CO₂ medium. An excitatory effect of CO₂ on a small number of neurons was also significant, although this was weak and transient compared to the inhibitory effect. Thermosensitivities of the neurons did not correlate with their CO₂ sensitivities. The influence of CO₂ tended to be more evident at higher temperatures. We conclude that the direct effect of CO₂ on PO thermosensitive neurons as well as on thermally insensitive neurons is mainly inhibitory.     

Ventrolateral medullary neurons projecting to the medial preoptic/anterior hypothalamic area through the medial forebrain bundle: an electrophysiological study in the rat

Summary A total of 152 ventrolateral medullary neurons was antidromically stimulated from both the medial preoptic/anterior hypothalamic area (MPOAH) and the medial forebrain bundle (MFB) in urethane anesthetized rats. These neurons were located primarily dorsal to the lateral reticular nucleus and could be readily classified in at least two groups, type I and type II cells on the basis of electrophysiological properties. The action potentials of type I cells had a shorter duration, and their conduction velocities ranged from 0.45 to 3.1 m/s. By contrast, type II cells, most predominantly observed, were characterized by a longer duration and an unusual shape of their action potential, and the antidromic propagation into the somatodendritic complex was often blocked. The conduction velocity (mean = 0.21 m/s) and absolute refractory period (mean = 2.63 ms) of type II cells are consistent with them having fine non-myelinated axons. Injection of 6-hydroxydopamine (6-OHDA), but not 5,7-dihydroxytryptamine, directly into the MFB blocked antidromic responses of 57% of type II cells tested. The residual type II cells whose antidromic responses were not affected by 6-OHDA were located significantly rostral to the 6-OHDA sensitive cells. Neither antidromic response of type I cells tested, on the other hand, was affected by 6-OHDA. The majority of type I cells were dramatically activated by noxious pinches of the tail, whereas the noxious stimuli produced no detectable change in the firing of type II cells. These data demonstrate that ventrolateral medullary neurons projecting to the MPOAH through the MFB are comprised of at least three distinct populations: 6-OHDA resistant fast conducting cells with somatic afferents, 6-OHDA sensitive and resistant slow conducting cells.     

The topical organization of the afferents to the caudatoputamen of the rat. A horseradish peroxidase study

The aim of the present study was to assess (1) whether the various brain areas known to send projections to the neostriatum of the rat (neocortex, thalamus, substantia nigra, ventral tegmental area and dorsal raphe nucleus) project to all parts of this structure, and (2) whether the subcortical projections show a topical organization. For these purposes, small deposits of horseradish peroxidase were delivered by iontophoretic application, so that the whole extent of the caudatoputamen could be covered in a total of 40 rats.Labeled cortical cells were present mainly in lamina V, and showed a roughly topographical organization. Small numbers of labelled cells were observed in the basal nucleus of the amygdala after injections into the dorsal and central parts of the caudatoputamen. The cells of origin of thalamic afferents to the neostriatum were found not only in the intralaminar nuclei, but also in various other anterior, ‘midline’, and posterior nuclei (e.g. the medial part of the medial geniculate body). In the thalamostriatal projection a topical organization was demonstrated, consisting of oblique thalamic zones, which cross the borders of several thalamic nuclei and project to different parts of the neostriatum. In the substantia nigra and ventral tegmental area many retrogradely labelled cells were present. This nigrostriatal projection appears to be organized along an oblique longitudinal neostriatal axis. The nucleus raphes dorsalis was labelled most abundantly after caudal and ventrolateral injections into the caudatoputamen.It is concluded that, despite the homogeneous cytoarchitectonic structure of the caudatoputamen in the rat, this brain area is rather heterogeneous as regards its afferent connections. In fact each part of the neostriatum receives a specific and unique combination of afferents. The main changes in the input of the neostriatum appear to occur along an oblique longitudinal axis, from the most rostromedial and dorsal part to the caudolateral and ventral part. Such a topographical organization suggests that the neostriatum is likely to be involved in very complex integrative functions involving several brain areas.     

Differential fos activation in virgin and lactating mice in response to an intruder

Lactating (L) mice display fierce aggression towards novel, male mice, while virgin (V) mice do not. This study compares patterns of brain activation in V and L mice in response to a novel intruder using immunohistochemical detection of Fos (Fos-IR). Animals were sampled 120 min after either a sham or real 10 min test with a male intruder. L mice were aggressive towards intruders, but V mice were not. In general, Fos-IR for both groups increased with exposure to an intruder, with L mice showing higher increases in Fos-IR than V mice. In only medial preoptic nucleus and ventral portion of bed nucleus of stria terminalis (BNST) was Fos-IR significantly increased in both groups with testing. In V mice, testing resulted in Fos-IR increases in an additional 10 regions examined that did not reach significance in L mice, including lateral septum, lateral and medial preoptic areas, and anterior hypothalamus. Fos-IR also increased with testing in nine regions unique to L mice, including the mitral and granular layers of accessory olfactory bulb, regions of the amygdala, dorsal BNST, and caudal portions of the hypothalamic attack area. These increases in Fos-IR with testing suggest alterations in the circuitry governing response to pheromonal cues and imply some commonalities between the circuitries governing maternal aggression and intermale aggression. These results support the hypothesis that pregnancy and lactation induce substantial changes in brain circuitry and function; changes that enable maternal defense of offspring by altering the neural response to an intruder male.     

Injection of substance P (SP) N-terminal fragment SP(1-7) into the ventral tegmental area modulates the levels of nucleus accumbens dopamine and dihydroxyphenylacetic acid in male rats during morphine withdrawal

The biologically active substance P (SP) N-terminal metabolite SP_1–7 has been reported to modulate several neural processes such as learning, locomotor activity and reaction to opioid withdrawal. Although all these processes are believed to be associated with dopaminergic transmission no evidence of an interaction between SP_1–7 and dopamine in the case of morphine withdrawal has so far been reported. Therefore, in this work we applied in vivo microdialysis to investigate the effect of SP_1–7 injection into the ventral tegmental area on dopamine release in nucleus accumbens of male rats during naloxone precipitated morphine withdrawal. The result showed that the heptapeptide enhances dopamine release and also elevates the level of the dopamine metabolite dihydroxyphenylacetic acid in this brain area. It was suggested that the observed action of the SP fragment on the dopamine system represents the underlying mechanism for a previously observed ability of SP_1–7 to counteract the aversion response to morphine withdrawal.     

Projections from the ventral tegmental area and mesencephalic raphe to the dorsal raphe nucleus in the rat

Summary The origins of the dopaminergic innervation of the rat dorsal raphe nucleus (NRD) have been investigated using a combination of fluorescent retrograde tracing and fluorescence histochemistry. Stereotaxic microinjections of True Blue were placed in the central, caudal and lateral portions of the NRD, and after 6–12 days survival the brains were processed for fluorescence histochemical detection of catecholamines. Retrogradely labeled neurons were searched for in the diencephalic A11 and A13 dopaminergic cell groups, substantia nigra, ventral tegmental area (VTA) and the linear, central superior and dorsal raphe nuclei. The various NRD injections consistently resulted in retrograde labeling of a small number of catecholamine-containing, presumed dopaminergic cell bodies, confined mainly to three regions: the VTA, the linear and central superior raphe nuclei and the NRD itself. The present findings indicate that not only dopaminergic neurons in the VTA but also the system of catecholamine-containing cells, extending dorsally and caudally from the VTA within the midline raphe area, project to the NRD. Although often similar in size, shape and distribution to the catecholaminergic neurons the majority of retrogradely labeled cells in these regions were, however, found to be non-catecholaminergic.Abbreviations 3 Principal oculomotor nucleus - 4 Trochlear nucleus - Aq Cerebral aqueduct - cp cerebral peduncle - cst cortico-spinal tract - dscp decussation of the superior cerebellar peduncle - DTg Dorsal tegmental nucleus - fr fasciculus retroflexus - IF Interfascicular nucleus - IP Interpeduncular nucleus - LL nucleus of the lateral lemniscus - ml medial lemniscus - mlf medial longitudinal fasciculus - mNV mesencephalic trigeminal nucleus - NLC Nucleus linearis caudalis - NLR Nucleus linearis rostralis - NRD Dorsal raphe nucleus - PAG Periaqueductal grey - PN Pontine nucleus - PRN Pontine raphe nucleus - R Red nucleus - RCS Nucleus raphe centralis superior - SN Substantia nigra - VTA Ventral tegmental area - VTg Ventral tegmental nucleus