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111.
目的 观察失血性休克大鼠中脑导水管周围灰质(PAG)腹外侧区的一氧化氮合酶(NOS)阳性神经元的变化。方法 取雄性SD大鼠20只随机分成4组,即对照组(假手术组)、休克时组、休克45 min组和休克90 min组。对照组仅进行左股动脉插管而不放血;其他各组经左股动脉插管放血复制失血性休克模型。分别在休克时、休克45 min和休克90 min灌注固定后取脑干进行冰冻切片,行NADPH-d组化染色观察,并对各组PAG腹外侧区尾段的NOS阳性神经元和其背内侧NOS阳性突起密度进行比较。结果 PAG腹外侧区尾段的NOS阳性神经元密度的变化无统计学意义(P〉0.01),但在失血性休克后NOS阳性神经元染色明显加深,其背内侧突起增密,变化有统计学意义(P〈0.01)。结论 大鼠PAG腹外侧区的NOS阳性神经元可能参与了失血性休克的发生发展,并且发挥着影响。 相似文献
112.
Thermogenesis in the brown adipose tissue (BAT) is activated by the stimulation of the ventromedial hypothalamic nucleus (VMH). Local warming of the preoptic area (PO) suppresses this response. Injection of the GABA(A) receptor antagonist bicuculline into the caudal periaqueductal gray (cPAG), where excitatory neurons for BAT thermogenesis are located, did not influence the suppressive effect of PO warming. On the other hand, after bicuculline injection into the raphé pallidus, where excitatory neurons for BAT thermogenesis are also located, VMH stimulation produced BAT thermogenesis even during PO warming. The present results suggest that the inhibitory signal from the PO reaches the raphé pallidus and not the cPAG for the control of BAT thermogenesis. 相似文献
113.
Analgesia and c-Fos expression in the periaqueductal gray induced by electroacupuncture at the Zusanli point in rats 总被引:3,自引:0,他引:3
The need to use anaesthetised or restrained animals in acupuncture research in laboratory animals may represent a confounding variable, since both anaesthesia and stress alter the pain threshold and the activity of pain-related brain areas. In the current study we assessed the participation of the periaqueductal gray (PAG) in electroacupuncture's (EA) analgesic effects applied to the Zusanli point (36S) under carefully controlled stress conditions. Repeated immobilisation protocols (6 days, 1 h/day and 13 days, 2 h/day) were used to diminish the influence of acute immobilisation stress on c-Fos expression and analgesia (tail-flick test) induced by electroacupuncture on the 36S point (EA36S). Animals submitted to immobilisation alone (IMMO) or to electroacupuncture (100 Hz, 2-4 V, faradic wave) on a non-point region (EANP) were compared with animals submitted to electroacupuncture on the 36S point. In animals not previously submitted to repeated immobilisation, electroacupuncture on the 36S point induced analgesia and c-Fos expression in the PAG was not different from that induced by electroacupuncture at a non-acupuncture point. In animals submitted to repeated immobilisation (repeated immobilisation for 6 days or repeated immobilisation for 13 days), however, electroacupuncture on point 36S led to higher levels of analgesia and c-Fos expression, specifically in the ventrolateral PAG (vlPAG), as compared with animal groups subjected only to immobilisation or to electroacupuncture on a non-point. Our findings endorse previous results, and point to a specific part of the PAG involved in the effects of electroacupuncture at the Zusanli point. 相似文献
114.
The urethrogenital (UG) reflex is a spinal sexual reflex that consists of autonomic and somatic nerve activity and vaginal, uterine, and anal sphincter contractions. The UG reflex is under tonic descending inhibition by neurons in the region of the nucleus paragigantocellularis (nPGi). The location of spinal neurons activated by the UG reflex was examined in the female rat using the immediate early gene, c-fos. In addition, the descending inputs from the nPGi onto fos-activated neurons was examined using the anterograde tracer biotin dextran amine injected into the nPGi. The UG reflex resulted in a significant increase in fos-positive nuclei in segments T12-S1, compared with experimental controls in which the UG reflex was not activated. Spinal circuits involved in the UG reflex include neurons relaying afferent information from the pudendal sensory nerve, in the dorsal horn and medial cord of L5-S1. Efferent output includes preganglionic neurons located in the lateral gray of L5-S1 and lateral and medial gray of T13-L2. Spinal interneurons involved in the UG reflex were found close to the preganglionic neurons and in the dorsal horn and intermediate and medial gray of T12-S1. NPGi inputs were found primarily on the autonomic efferents and interneurons in the medial and intermediate gray. These studies demonstrate multisegmental spinal circuits activated with the UG reflex and demonstrate that the descending inhibition from the nPGi is by means of preganglionic and somatic efferents and spinal interneurons closely associated with the efferent output. 相似文献
115.
Localized <Superscript>1</Superscript>H magnetic resonance spectroscopy in mainly cortical gray matter of patients with multiple sclerosis 总被引:3,自引:0,他引:3
Sarchielli P Presciutti O Tarducci R Gobbi G Alberti A Pelliccioli GP Chiarini P Gallai V 《Journal of neurology》2002,249(7):902-910
The brain water fraction (R), the brain water transverse relaxation time (T2), the atrophy index (α) and the absolute concentration
of the principal brain metabolites (NAA, Cho and Cr) were measured by localized proton magnetic resonance spectroscopy in
the occipito-parietal cortex (mainly gray matter) of 15 relapsing-remitting (R-R) multiple sclerosis (MS) patients, 15 secondary
progressive (SP) MS patients and 8 healthy subjects. Significantly lower values of N-acetylaspartate (NAA), creatine (Cr)
and the NAA/Cr ratio in the occipito-parietal cortex were detected in SP MS patients than in R-R MS and control subjects (p
< 0.01). Moreover, MS patients showed shorter T2 water relaxation times and reduced brain water fraction compared with controls.
Higher atrophy indices were also detected in the mainly occipito-parietal gray matter of MS patients, particularly in those
with the progressive form. These findings suggest that the pathological process in MS is not limited to either white matter
lesions or normal-appearing white matter but extends into the cortical gray matter (occipito-parietal), particularly in the
progressive form of the disease. This can involve changes in neural metabolism or neural shrinkage and neuron loss. The significant
increase in atrophy indices could be the expression of the relatively higher cerebrospinal fluid signal from the occipito-parietal
cortex, even in the absence of obvious cortical atrophy.
Received: 18 January 2001, Received in revised form: 16 January 2002, Accepted: 29 January 2002 相似文献
116.
Fos expression induced by warming the preoptic area in rats 总被引:1,自引:0,他引:1
Yoshida K Maruyama M Hosono T Nagashima K Fukuda Y Gerstberger R Kanosue K 《Brain research》2002,933(2):109-117
The preoptic area (POA) occupies a crucial position among the structures participating in thermoregulation, but we know little about its efferent projections for controlling various effector responses. In this study, we used an immunohistochemical analysis of Fos expression during local warming of the preoptic area. To avoid the effects of anesthesia or stress, which are known to elicit Fos induction in various brain regions, we used a novel thermode specifically designed for chronic warming of discrete brain structures in freely moving rats. At an ambient temperature of 22 degrees C, local POA warming increased Fos immunoreactivity in the supraoptic nucleus (SON) and the periaqueductal gray matter (PAG). Exposure of animals to an ambient temperature of 5 degrees C induced Fos immunoreactivity in the magnocellular paraventricular nucleus (mPVN) and the dorsomedial region of the hypothalamus (DMH). Concurrent warming of the POA suppressed Fos expression in these areas. These findings suggest that thermal information from the preoptic area sends excitatory signals to the SON and the PAG, and inhibitory signals to the mPVN and the DMH. 相似文献
117.
Serotonergic projections to the rostroventrolateral medulla from midbrain and raphe nuclei 总被引:4,自引:0,他引:4
Double-label fluoresence immunohistochemistry was performed to define serotonergic projections from the raphe and midbrain to the sympathoexcitatory region of the rostroventrolateral medulla (RVLM). Immunolabelling of cholera toxin B subunit retrogradely transported from the pressor region of the RVLM was combined with serotonin (5-HT) immunohistochemistry. Major sources of serotonergic input to the RVLM were shown to include the raphe obscurus, raphe pallidus and raphe magnus with a minor contribution from the ventrolateral, lateral and ventral regions of the periaqueductal gray matter, and the dorsal raphe nucleus. Serotonergic modulation of sympathoexcitatory neurons may establish patterns of sympathetic nerve activity evident in many aspects of cardiovascular regulation. 相似文献
118.
To determine if ventrolateral periaqueductal gray contains neurons that selectively increase their discharge activity before and during rapid eye movement (REM) sleep, and hence might furnish GABAergic inhibition of monoaminergic neurons, we recorded the extracellular activity of 33 neurons across sleep-wakefulness in freely behaving cats. Several types of state-specific neuronal populations were found in the periaqueductal gray, although we did not find any neurons that had a tonic discharge increase before and during REM. Thus, these data suggest that, although periaqueductal gray neurons may regulate phasic components of REM sleep, they do not have the requisite tonic pre-REM and REM activity to be a source of GABAergic inhibition of monoaminergic neurons. 相似文献
119.
图像的阈值分割及其应用 总被引:1,自引:0,他引:1
目的 对被检测物体和背景反差较大的图像进行分割。方法 首先绘出要分割图像的灰度直方图;根据直方图选出适当的阈值;最后利用所选定的阈值对图像进行分割。结果 阈值法能把被检测物体和背景反差较大的图像分割。结论 对于被检测物体和背景反差较大的图像,阈值法是一种简单、有效、可靠的分割方法。 相似文献
120.
In recent years, an increase in abuse of anabolic androgenic steroids (AAS) has been seen among individuals not directly connected to sports. Clinical evidence suggests that abuse of these steroids may result in profound changes in personality, expressed by depressive symptoms, irritability and increased aggression. It is still unknown whether these alterations are related to changes in any particular transmitter system or whether they are persistent or reversible. In this study we focused on AAS effect on the endogenous dynorphin and enkephalin system in the brain. Male rats were given intramuscular injections of the AAS nandrolone decanoate (15 mg/kg), once daily for 2 weeks. The levels of the opioid peptide immunoreactivities (ir) were assessed by radioimmunoassay in two groups immediately after the treatment and in two other groups after additional 3 weeks without any drug treatment (recovery period). The result indicates that chronic AAS treatment increased the activity in the dynorphin B- and Met-enkephalin-Arg(6)Phe(7)-ir in the hypothalamus, striatum and periaqueductal gray (PAG) compared to controls. In addition, the steroid induced an imbalance between the dynorphin and the enkephalin opioid system in the nucleus accumbens, hypothalamus and PAG. This imbalance remained after the recovery period. Since increased peptide activity was found in brain regions regulating emotions, dependence, defensive reactions and aggression, it was suggested that the actual endogenous opioid systems are involved in previously reported AAS-induced changes in these behaviours. 相似文献