大鼠中脑导水管周围灰质和中缝核簇内P物质受体定位分布的免疫细胞化 …

本研究用免疫细胞化学染色技术对大鼠中脑导水管周围灰质（ＰＡＧ）和中缝核簇内Ｐ物质受体的精确定位分布进行了系统地观察，Ｐ物质受体阳性的神经元胞体和纤维主要密集地分布于ＰＡＧ组织的背侧部，中段的外侧部和尾段的腹侧部，在线形核，中缝背核，中缝正中核，中缝桥核，中缝大核和中缝隐核可见中等密度至高密度的阳性神经元胞体和纤维，在中央下核和中缝苍白核内仅见少量阳性纤维。     

大鼠脑干运动核内γ—氨基丁酸B受体1亚型的定位分布

用γ氨基丁酸B受体1亚型（GＡＢBR1）特异性抗体免疫细胞化学染色技术,研究了其在大鼠脑干运动核团内的定位分布,结果显示：密集浓染的GABABR1样阳性神经元胞体、纤维和终末分布于E-W核、上涎核、疑核和迷走神经背核;三叉神经运动核、面神经核内可见中等密度且浓梁的GABABR1样阳性神元胞体、纤维和终末;中等密度淡染的阳性神经元胞体、纤维和终末见于动眼神经核、滑车神经核和舌下神经核;散在的阳性胞体、纤维和终末见于外展神经核和下涎核。本研究的结果说明GABABR1样阳性结构在脑干不同运动核内的分布存在差异。     

大鼠脑干SP能神经元向腰骶髓后连合核的投射

采用荧光金逆行标记和免疫荧光组织化学技术，观察了大鼠脑干ＳＰ能神经元向腰骶髓后连合核（ＤＣＮ）的投射状况。将ＦＧ压力注入ＤＣＮ后，脑干中缝苍白核、中缝隐核、中缝大核和巨细胞网状核α部腹外侧部的一些ＦＧ逆标神经元呈现ＳＰ样免疫反应阳性。结果表明，脑干的ＳＰ能下行纤维可终止于脊髓ＤＣＮ区。     

大鼠GAD样,甘氨酸样和SP样阳性终末与三叉神经中脑核神经 …

应用免疫荧乐组织化学双重染色和三重染色技术,在激光共聚焦显微镜下观察了大鼠三叉神经中脑核（Ｖｍｅ）内谷氨酸脱羧酶（ＧＡＤ）样、甘氨酸（Ｇｌｙ）样和Ｐ物质（ＳＰ）样阳性终末与磷酸激活的谷氨酰胺酶（ＰＡＧ）样阳性神经元之间的联系。结果显示：①几乎所有的Ｖｍｅ神经元均呈ＰＡＧ样免疫阳性,这些神经元绝大多数为大的假单极神经元。②密集分布的ＧＡＤ样或Ｇｌｙ样免疫阳性的神经终扣分别聚集于ＰＡＧ样阳性的Ｖｍｅ神     

疼痛及针刺镇痛时孤啡呔受体mRNA的变化

目的：观察大鼠在福尔马林致痛及针刺镇痛时孤啡肽受体ｍＲＮＡ在一些与镇痛有关核团的变化情况。方法：采用原位杂交组织化学技术。结果：电针后１０ｈ，导水管周围腹侧区、中缝背核及中缝大核内孤啡肽受体ｍＲＮＡ阳性神经元数增多；而在大鼠脚掌注射福尔马林后，上述核团内孤啡肽受体ｍＲＮＡ阳性神经元数却明显减少；电针并注射福尔马林，脑内孤啡肽受体ｍＲＮＡ水平介于单用电针和福尔马林之间。结论：电针能促进孤啡肽受体的合成而伤害性刺激抑制孤啡肽受体的合成。     

大鼠导水管周围灰质注射谷氨酸可Barrington使核神经 …

形态学研究已发现大鼠内侧视前区（ＭＰＯ）和导水管周围灰质（ＰＡＧ）发出大量轴突，投射至与排尿反射密切相关的Ｂａｒｒｉｎｇｔｏｎ核。本研究试图通过注射谷氨酸钠到ＭＰＯ或ＰＡＧ后，观察Ｂａｒｒｉｎｇｔｏｎ核内的Ｆｏｓ表达情况，来了解以上两通路的性质。将谷氨酸钠注射到ＭＰＯ后，只有少量Ｆｏｓ阳性神经元出现在Ｂａｒｒｉｎｇｔｏｎ核。而将谷氨酸钠注射到ＰＡＧ后，Ｂａｒｒｉｎｇｔｏｎ核内出现大量的Ｆｏｓ阳性神     

P物质和谷氨酸介导辣椒素引起的脊髓γ—氨基丁酸的释放

以前的实验证明辣椒素急性处理外周神经可导致初级传入末梢大量释放Ｐ物质，同时也观察到脊髓背角浅层ＧＡＢＡ的排空。本研究的目的在于探讨外周施加辣椒素激活背角ＧＡＢＡ能神经元，是否与初级传入末梢释放的递质有关。结果表明，外周胫神经辣椒素处理３０分钟即可引起的同侧背角浅层ＧＡＢＡ免疫反应产物（ＧＡＢＡ—ＩＲ）的明显减少，予先用ＮＫ—１受体桔抗剂Ｓｐａｎｔｉｄｅ（５０ｎＭ）或ＮＭＤＡ受体拮抗剂ＡＰＶ（１００μＭ）灌流脊髓腰膨大表面，可部分阻断辣椒素引起的ＧＡＢＡ—ＩＲ密度和ＧＡＢＡ—ＩＲ阳性神经元数目的减少，使ＧＡＢＡ—ＩＲ有不同程度的恢复。本文讨论了初级传入末梢释放的Ｐ物质和兴奋性氨基酸与ＧＡＢＡ能神经元在脊髓痛觉信息调制中的作用。     

大鼠导水管周围灰质注射谷氨酸可使Barrington核神经元表达Fos

形态学研究已发现大鼠内侧视前区（ＭＰＯ）和导水管周围灰质（ＰＡＧ）发出大量轴突,投射至与排尿反射密切相关的Ｂａｒｒｉｎｇｔｏｎ 核。本研究试图通过注射谷氨酸钠到ＭＰＯ或ＰＡＧ后,观察Ｂａｒｒｉｎｇｔｏｎ 核内的Ｆｏｓ表达情况,来了解以上两通路的性质。将谷氨酸钠注射到ＭＰＯ后,只有少量Ｆｏｓ阳性神经元出现在Ｂａｒｒｉｎｇ－ｔｏｎ 核。而将谷氨酸钠注射到ＰＡＧ后,Ｂａｒｒｉｎｇｔｏｎ 核内出现大量的Ｆｏｓ阳性神经元。此结果提示,ＰＡＧ可能对大鼠脑桥排尿反射活动具有兴奋性调节作用。     

大鼠脑-干 SP能神经元向腰骶髓后连合核的投射

采用荧光金逆行标记和免疫荧光组织化学技术,观察了大鼠脑干SP能神经元向腰骶髓后连合核(DCN)的投射状况.将FG压力注入DCN后,脑干中缝苍白核、中缝隐核、中缝大核和巨细胞网状核α部腹外侧部的一些FG逆标神经元呈现SP样免疫反应阳性.结果表明,脑干的SP能下行纤维可终止于脊髓DCN区.     

大鼠中脑导水管周围灰质向孤束核的直接投射

用ＰＨＡ－Ｌ和ＷＧＡ－ＨＲＰ顺行追踪方法,对大鼠中脑导水管周围灰质（ＰＡＧ）向孤束核的投射进行了研究。结果如下：（１）ＰＨＡ－Ｌ和ＷＧＡ－ＨＲＰ顺标纤维和终末在孤束核内的分布状态基本一致,内侧亚核最多,连合亚核、腹外侧亚核和腹侧亚核次之,中间亚核内最少。无论注射区在ＰＡＧ的尾段还是吻段,孤束核的尾中段内的标记纤维和终末均多于吻段。（２）ＰＡＧ尾段向孤束核的投射多于ＰＡＧ吻段。（３）ＰＡＧ腹外侧区向孤束核的投射较多,而背外侧区较少（尾段）或缺如（吻段）。根据作者过去的结果和本实验证据,可见ＰＡＧ向孤束核的投射通路存在定位投射关系。     

Heterogeneous distribution of neurotensin-like immunoreactive neurons and fibers in the midbrain periaqueductal gray of the rat

The midbrain periaqueductal gray (PAG) has been shown to be a site where various manipulations induce pain suppression. Recent physiological evidence (Behbehani and Pert, 1984; Behbehani et al., 1987) suggests that neurotensin has pronounced physiological actions in PAG and effects pain suppression. We have performed immunohistochemical studies in order to determine the magnitude and distribution of neurotensin-like immunoreactive (NT-IR) cell bodies and fibers in PAG. NT-IR cell bodies were common throughout PAG, although there were more in the caudal than the rostral half. NT-IR neurons were much more numerous in the ventral than the dorsal half of PAG, and some appeared to be located within the dorsal raphe nucleus. The pattern of NT-IR fibers was analyzed with the aid of image enhancement/analysis and densitometry. The fibers were found to be heterogeneously distributed, being most heavily concentrated in the region adjacent to the cerebral aqueduct in the caudal two-thirds of PAG. The distribution of NT fibers closely matches sites where exogenously applied NT elicits long-lasting excitation of PAG neurons (Behbehani et al., 1987). Based on the known physiological and behavioral actions of NT in PAG, the present anatomical results suggest that NT acts on elements located predominantly in the medial and ventrolateral parts of PAG. Neurons activated by NT may project directly to the nucleus raphe magnus and adjacent ventral medulla (Behbehani and Pert, 1984) to activate neurons that project to the spinal cord and modulate nociceptive circuits.     

Serotonergic projections from the midbrain periaqueductal gray and nucleus raphe dorsalis to the nucleus parafascicularis of the thalamus.

By a double-labeling method combining the retrograde tracing of horseradish peroxidase and the immunocytochemical technique, serotonin-like immunoreactive neurons in the midbrain periaqueductal gray (PAG) and nucleus raphe dorsalis (DR) of the rat were observed to send projection fibers to the nucleus parafascicularis of the thalamus bilaterally with an ipsilateral dominance. These serotonin-containing projecting neurons were observed mainly at the middle-caudal levels of the ventrolateral subdivision of the PAG and less at the middle-rostral levels of the DR.     

Serotonergic projections from the midbrain periaqueductal gray and nucleus raphe dorsalis to the nucleus parafasccicularis of the thalamus

By a double-labeling method combining the retrograde tracing of horseradish peroxidase and the immunocytochemical technique, serotonin-like immunoreactive neurons in the midbrain periaqueductal gray (PAG) and nucleus raphe dorsalis (DR) of the rat were observed to send projection fibers to the nucleus parafascicularis of the thalamus bilaterally with an ipsilateral dominance. These serotonin-containing projecting neurons were observed mainly at the middle-caudal levels of the ventrolateral subdivision of the PAG and less at the middle-rostral levels of the DR.     

Origins of endomorphin-immunoreactive fibers and terminals in different columns of the periaqueductal gray in the rat

Endomorphin 1 (EM1) and endomorphin 2 (EM2) are endogenous ligands for mu-opioid receptors (MOR). In the central nervous system, EM-immunoreactive (IR) neuronal cell bodies are located mainly in the hypothalamus and the nucleus tractus solitarius (NTS). EM-IR fibers and terminals are found widely distributed in many brain areas, including the different columns of the periaqueductal gray (PAG). The hypothalamus, NTS, and PAG are closely involved in modulation of vocalization, autonomic and neuroendocrine functions, pain, and defensive behavior through endogenous opioid peptides that bind to the MOR in these regions. Projections exist from both the hypothalamus and the NTS to the PAG. In order to examine whether there are EM1- and/or EM2-ergic projections from the hypothalamus and NTS to the PAG, immunofluorescence histochemistry for EM1 and/or EM2 was combined with fluorescent retrograde tracing. In rats that had Fluoro-Gold (FG) injected into different columns of the PAG, some of the EM1- or EM2-IR neurons in the hypothalamus, but none in the NTS, were labeled retrogradely with FG. The majority of the EM1/FG and EM2/FG double-labeled neurons in the hypothalamus were distributed in the dorsomedial nucleus, areas between the dorsomedial and ventromedial nucleus, and arcuate nucleus; a few were also seen in the ventromedial, periventricular, and posterior nucleus. The present results indicate that the EM-IR fibers and terminals in the PAG originate principally from the hypothalamus. They also suggest that EMs released from hypothalamus-PAG projecting neurons might mediate or modulate various functions of the PAG through binding to the MOR.     

Overlapping distributions of orexin/hypocretin- and dopamine-beta-hydroxylase immunoreactive fibers in rat brain regions mediating arousal,motivation, and stress

A double-label immunohistochemical study was carried out to investigate overlap between dopamine-beta-hydroxylase (DbetaH) -immunopositive projections and the projections of hypothalamic neurons containing the arousal- and feeding-related peptide, orexin/hypocretin (HCRT), in rat brain. Numerous intermingled HCRT-immunopositive and DbetaH-immunopositive fibers were seen in a ventrally situated corridor extending from the hypothalamus to deep layers of the infralimbic cortex. Both fiber types avoided the nucleus accumbens core, caudate putamen, and the globus pallidus. In the diencephalon, overlap was observed in several hypothalamic areas, including the perifornical, dorsomedial, and paraventricular nuclei, as well as in the paraventricular thalamic nucleus. Intermingled HCRT-containing and DbetaH-containing fibers extended from the hypothalamus into areas within the medial and central amygdala, terminating at the medial border of the lateral subdivision of the central nucleus of the amygdala. Dense overlap between the two fiber types was also observed in the periaqueductal gray, particularly in the vicinity of the dorsal raphe, as well as (to a lesser extent) in the ventral tegmental area, the retrorubral field, and the pedunculopontine tegmental nucleus. Hypocretin-containing cell bodies, located in the perifornical and lateral hypothalamus, were embedded within a dense plexus of DbetaH-immunopositive fibers and boutons, with numerous cases of apparent contacts of DbetaH-containing boutons onto HCRT-immunopositive soma and dendrites. HCRT-containing fibers were observed amid the noradrenergic cells of the locus coeruleus, and in the vicinity of the A1, A2, and A5 cell groups. Hence, the projections of these two arousal-related systems, originating in distinctly different parts of the brain, jointly target several forebrain regions and brainstem monoaminergic nuclei involved in regulating core motivational processes.     

Mapping of neuropeptide Y-like immunoreactivity in the feline hypothalamus and hypophysis

The distribution of neuropeptide Y (NPY) in the cat hypothalamus and hypophysis was studied with the indirect immunofluorescence technique of Coons and co-workers (Coons, Leduc, and Connolly: J. Exp. Med. 102:49-60, 1955), which provided a detailed map of NPY-like immunoreactive neurons. The immunolabelling was detected in cell bodies, fibers, and terminallike structures widely distributed throughout the whole hypothalamus. A large population of medium-sized NPY-like immunoreactive cell bodies was localized in the area of arcuate nucleus. The number of immunoreactive cell bodies visualized was dramatically increased after intracerebroventricular injections of colchicine. Numerous immunolabelled cell bodies were also visible in the median eminence and scattered in the lateral hypothalamic area. Dense plexuses of NPY-immunoreactive fibers were observed in the arcuate nucleus, internal layer of median eminence, periventricular zone, and paraventricular nucleus. Other regions of hypothalamus displaying numerous NPY-like immunoreactive fibers included dorsal and ventrolateral hypothalamic areas. In contrast, certain hypothalamic areas were almost devoid of NPY-like immunoreactive fibers-namely, the mammillary bodies and suprachiasmatic nucleus. Finally, in neurohypophysis, bright immunofluorescent fibers were observed along the pituitary stalk and penetrating the neural lobe. These results suggest the widespread distribution of the NPY-containing neuronal systems in the cat hypothalamus and hypophysis.     

Cellular basis for the effects of substance P in the periaqueductal gray and dorsal raphe nucleus

Substance P (SP) is known to act at supraspinal sites to influence pain sensitivity as well as to promote anxiety. The effects of SP could be mediated in part by actions in the periaqueductal gray (PAG) and the dorsal raphe nucleus (DRN), adjoining mesencephalic cell groups that are strategically positioned to influence both nociception and mood. Previous studies have indicated that SP regulates both enkephalin and serotonin neurotransmission in these brain regions. To determine the mechanism underlying the effects of SP in the PAG and DRN, the distribution of the principal receptor for SP, the neurokinin 1 (NK1) receptor, was examined with respect to other neurotransmitter markers. PAG neurons that had NK1 receptor immunolabeling were interdigitated with and received contacts from enkephalin-containing neurons. However, only a few (16/144; 11%) neurons with NK1 receptor also contained enkephalin immunoreactivity after colchicine treatment. In the DRN, dendrites containing NK1 receptor were selectively distributed in the dorsomedial subdivision. The majority (132/137; 96%) of these dendrites did not contain immunoreactivity for the serotonin-synthesizing enzyme tryptophan hydroxylase. In contrast, neuronal profiles with NK1 receptor in both the PAG and the DRN often contained immunolabeling for glutamate. Light and electron microscopic examination revealed that 48-65% of cell bodies and dendrites with NK1 receptor were dually immunolabeled for glutamate. These data suggest that SP directly acts primarily on glutamatergic neurons in the PAG and DRN. To a lesser extent, enkephalin-containing neurons may be targeted. Through these actions, it may subsequently influence activity of larger populations of neurons containing enkephalin as well as serotonin. This circuitry could contribute to, as well as coordinate, effects of SP on pain perception and mood.     

Retrograde axonal transport following injection of [3H]-serotonin into the olfactory bulb. II. Radioautographic study

Radioautography was used to study the intraneuronal distribution of [3H]-serotonin (5-HT) and/or its derivatives selectively taken up by the olfactory bulb (OB) serotonergic terminals and subsequently transported to their parent cell bodies in the midbrain raphe nuclei. This was done 24 h after injection of [3H]5-HT into the main OB of rats either pretreated or not with monoamine oxidase (MAO) inhibitor. A prior mechanical obstruction of the rostral ventricular cavities prevented diffusion of the tracer towards cerebrospinal fluid. Heavily labelled nerve cell bodies were found mainly in the ipsilateral raphe dorsalis nucleus (RDN) and to a lesser extent in the raphe centralis nucleus. The radioautographic reaction often extended to dendritic processes while sparing the nucleus. A diffuse reaction was also observed but limited to the raphe area. The supraependymal 5-HT fibers were found to be free of labelling. Neither local destruction of catecholaminergic terminals with 6-OHDA, nor absence of MAO inhibition, impaired this radioautographic pattern, while destruction of serotonergic terminals with 5,6-dihydroxytryptamine in OB resulted in the disappearance of labelled axonal varicosities and neurons in the OB and the RDN respectively. At the electron microscopy level, labelled cell bodies in the RDN were medium-sized (12-15 micrometers). Silver grains were localized mainly on mitochondria and, to a lesser extent, on lysosomes and endoplasmic reticulum but spared the nucleus and the nucleolus. Silver grains were also found near the nuclear membrane and outside the neuronal membrane. The observation of heavy metal impregnated thick sections confirmed the preferential localization of silver grains on mitochondria with or without inhibition of MAO. These results could account for the subcellular compartments involved in the retrograde axonal transport of [3H]5-HT and its subsequent degradation and/or dendritic release.     

Distribution of galaninlike immunoreactivity in the rat central nervous system

The localization of galanin (GAL) immunoreactive (IR) neuronal structures in the rat central nervous system has been investigated by using the indirect immunofluorescence technique. GAL-IR structures were seen in high concentrations in the hypothalamus, medulla oblongata, and spinal cord. Less extensive systems were detected in the telencephalon, thalamus, mesencephalon, and pons, while virtually no GAL-positive structures were seen in the olfactory bulb and cerebellum. Major populations of cell bodies staining for GAL-like material were seen in many areas. In the telencephalon somata were revealed in the bed nucleus of stria terminalis, in the nucleus of the diagonal band, medial septum, and in the medial aspects of the central amygdaloid nucleus, and in small numbers in cortical areas. The anterodorsal and periventricular nuclei of the thalamus contained positive cell bodies. In the hypothalamus GAL-IR somata were seen in the medial and lateral preoptic nuclei, arcuate nucleus, periventricular nucleus, in the dorsomedial nucleus, in the medial forebrain bundle area, in the tubular, caudal, accessory, supraoptic, and paraventricular magnocellular nuclei and lateral to the mammillary recess. The dorsal raphe nucleus hosted a large number of GAL-positive somata. Locus coeruleus of the pons contained a large number of GAL-IR perikarya. In the medulla oblongata positive somata were found in the caudal spinal trigeminal nucleus, the nucleus of the solitary tract, and in the ventral lateral area just rostral to area postrema. Small cell bodies were detected in the superficial layers of the dorsal horn of the spinal cord at all levels and in lamina X at lumbar levels. Analysis of GAL-positive fibers in the telencephalon revealed highly or medium-dense networks in the lateral septal nucleus, in the bed nucleus of stria terminalis, and in the central and medial amygdaloid nuclei. Positive fibers were found in the thalamus in and around the periventricular nucleus as well as in the lateral habenular nucleus and extending in a lateral, caudal direction from the third ventricle and fasciculus retroflexus to the lateral tip of the medial lemniscus. In the hypothalamus the external layer of the median eminence contained a very dense fiber network. Dense or medium-dense GAL-IR networks were detected in the periventricular nucleus, throughout the medial and lateral preoptic areas, in the medial forebrain bundle area, in the dorsomedial nucleus, and lateral to the mammillary recess. In the pons GAL-IR fibers were seen in the parabrachial nuclei, dorsal to the superior olive, and in the periaqueductal central gray.(ABSTRACT TRUNCATED AT 400 WORDS)     

A comparative study of the immunohistochemical localization of a presumptive proctolin-like peptide, thyrotropin-releasing hormone and 5-hydroxytryptamine in the rat central nervous system

A proctolin (PROC)-like peptide was studied immunohistochemically in the hypothalamus, lower brainstem and spinal cord of the rat using an antiserum against PROC conjugated to thyroglobulin. Neuronal cell bodies containing PROC-like immunoreactivity (PROC-LI) were observed in the dorsomedial, paraventricular and supraoptic nuclei of the hypothalamus and in the nucleus raphe magnus, nucleus raphe pallidus, nucleus raphe obscurus and nucleus interfascicularis nervi hypoglossi in the medulla oblongata. Fibers containing PROC-LI were seen in the median eminence and in other hypothalamic nuclei, and in the lower brainstem in cranial motor nuclei including the dorsal motor nucleus of the vagus nerve, the motor trigeminal nucleus, the facial nucleus and nucleus ambiguous, and in lower numbers in the nucleus of the solitary tract and locus coeruleus. Fibers containing PROC-LI were also located in the spinal cord, in the intermediolateral cell column at thoracic levels and in the ventral horns at all levels of the spinal cord. After transection of the spinal cord, all PROC-immunoreactive fibers below the lesion disappeared. Following injection of Fast blue into the thoracic spinal cord, retrogradely labeled cells in the nuclei raphe pallidus, obscurus and magnus and nucleus interfasciculari nervi hypoglossi were seen to contain PROC-LI. PROC-LI had a similar distribution as thyrotropin-releasing hormone (TRH)-LI in the above-mentioned areas and coexistence of TRH-LI and PROC-LI was shown in cell bodies in the hypothalamus and medulla oblongata. PROC-LI could also be shown to coexist with 5-hydroxytryptamine (5-HT)-LI in neuronal cell bodies in the lower brainstem. The results demonstrate the occurrence of a PROC-like peptide in the mammalian nervous system, and these neurons seem to be at least largely identical to previously described TRH systems. A possible involvement of the PROC-like peptide in spinal motor control is discussed in relation to the well-established role of PROC in control of motor behavior in insects and invertebrates.