Relation between the septal nuclei and the amygdaloid complex of the brain of the cat

By means of retrograde and anterograde transport of horseradish peroxidase method it has been demonstrated in two series of experiments with injecting the enzyme into separate septal nuclei and the amygdaloid complex in cats that most of amygdaloid nuclei (cortico-medial, central and baso-lateral) are reciprocally connected only with two nuclei in the septum: with the nucleus of the diagonal bundle of Broca and with the nucleus of the terminal strip bed. The projections studied are topically organized. The cortico-medial and basal nuclei of the amygdaloid complex are reciprocally connected with the ventral part of the diagonal bundle of Broca and with the terminal strip bed nucleus. The central nucleus of the amygdala has reciprocal projections only with the terminal strip bed nucleus, and with the ventral part of the diagonal bundle of Broca it has only a unilateral connection. On the contrary, the lateral nucleus of the amygdala is reciprocally connected with the ventral part of the diagonal bundle of Broca, and is only projected on the terminal strip bed nucleus without getting any projections from it.     

Distribution of horseradish peroxidase-labeled neurons giving rise to descending fiber systems in the basal ganglia and hypothalamus in cats

The distribution of neurons giving rise to various descending fiber systems to brain-stem structures in the basal ganglia (including amygdaloid nuclei) and hypothalamus of the cat was studied by the retrograde axonal transport of horseradish peroxidase method. Neurons in the medial part of the central nucleus and of the magnocellular part of the basal nucleus of the amygdaloid group were shown to send axons to the dorsal hippocampus, substantia nigra, lateral part of the central gray matter, and the mesencephalalic reticular formation and also to the region of the locus coeruleus and the lateral medullary reticular formation at the level of the inferior olives. The predominant source of projections to the hypothalamus and brainstem structures is the central amygdaloid nucleus, which also sends projections to the nucleus of the tractus solitarius, the dorsal motor nucleus of the vagus nerve, and the superior cervical segments of the spinal cord. Uncrossed fiber systems descending from the basal ganglia terminate at the level of the pons, whereas uncrossed and crossed fiber systems descending from the dorsal and ventromedial hypothalamus can be traced into the spinal cord. The possible role of nuclei of the amygdaloid group, the hypothalamus, and their efferent projections in the regulation of somatic and vegetative functions and also of complex behavioral reactions is discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 13, No. 1, pp. 14–23, January–February, 1981.     

电刺激杏仁复合体诱发心律失常及其下行神经通路的初步探讨

电刺激杏仁复合体能诱发心律失常。心律失常的类型为心动过缓伴室性或结性期外收缩。刺激杏仁复合体不同亚核均能诱发心律失常,不同类型的心律失常在核内具有相应的代表点。心律失常发作与杏仁局部区域诱发的爆发性后放电有关。推测杏仁复合体内神经元过度激活可能通过杏仁-迷走神经运动背核及杏仁-下丘脑外侧区等通路下行,使心率减慢、房室传导阻滞而导致心律失常。     

Ascending projections to the hypothalamus and limbic nuclei from the dorsolateral pontine tegmentum: a biochemical and electron microscopic study.

Axons arising from the dorsolateral pontine tegmentum of the rat were traced in various hypothalamic and limbic nuclei by the electron microscopic degeneration method (0.5-8 day survival times) and by measuring regional norepinephrine (NE) concentrations after 12 days of survival using a radioenzymatic method. Significant reductions (41-85%) in NE contents were observed in the supraoptic, arcuate, basal and lateral amygdaloid nuclei and in the hippocampus 12 days after the bilateral electrolytic lesions of the locus coeruleus. No changes in NE concentrations were observed in the ventromedial, septal, central amygdaloid nuclei, in the median eminence and olfactory tubercle. Parabrachial lesions resulted in a decrease of NE content only in the olfactory tubercle. By means of electron microscopy terminal degeneration was found in the hypothalamic paraventricular, dorsomedial nuclei, in the median eminence, in the bed nucleus of the stria terminalis, in the central, lateral and basal amygdaloid nuclei, in the hippocampus and in the anterior ventral thalamic nucleus.     

Fos Expression in the Rat Brain After Intraperitoneal Injection of Staphylococcus Enterotoxin B and the Effect of Vagotomy

The current study was designed to locate the neuronal activation in rat brain following intraperitoneal injection of Staphylococcus enterotoxin B (SEB) and observe the consequence of preliminary subdiaphragmatic vagotomy on SEB-induced brain Fos expression to clarify the role of the vagus nerve in sensation and transmission of abdominal SEB stimulation. The results showed that intraperitoneal SEB (1 mg/kg) induced a robust Fos expression in widespread brain areas. A significant increase of Fos immunoreactive cells were observed in the solitary tract nucleus, locus ceruleus, lateral parabrachial nucleus, ventrolateral part of central gray, medial amygdaloid nucleus, central amygdaloid nucleus, ventromedial part of thalamus, dorsomedial part of thalamus, hypothalamic paraventricular nucleus, lateral habenula, and lateral septum nucleus following SEB challenge. In hypothalamic paraventricular nucleus, in addition to the dense Fos expression in the parvocellular portion, some Fos-positive cells were also observed in the anterior magnocellular nucleus of the complex. Double immunofluorescence studies showed that these Fos-immunoreactive cells were mostly oxytocinergic. The results also showed that subdiaphragmatic vagotomy largely attenuated, but not totally abrogated, the brain Fos expression induced by abdominal administration of SEB. Our data suggest that peripheral SEB stimulation can induce activation of neurons in widespread brain areas and that the vagus plays a crucial role in transmitting the signal of abdominal immune stimulation to the brain.     

Supratrigeminal neurons mediate the shortest, disynaptic pathway from the central amygdaloid nucleus to the contralateral trigeminal motoneurons in the rat

Stimulation of the supratrigeminal area (STA) of the rat induced a monosynaptic EPSP in most mylohyoid-digastric motoneurons and a monosynaptic IPSP or EPSP in the majority of masseteric ones, contralaterally. Stimulation of the central amygdaloid nucleus induced the ipsilateral STA activity immediately followed by the contralateral mylohyoid nerve activities. The same amygdaloid stimulated excited 19 of 46 STA neurons, which were antidromically identified to project to the contralateral trigeminal motor nucleus. Nine of these were monosynaptically excited. The mean of the antidromic and monosynaptic latencies of these neurons explains the mean onset latencies of the amygdaloid influences on the contralateral trigeminal motoneurons. Therefore, the shortest crossing amygdalo-motoneuronal pathway is probably disynaptic and mediated by commissural STA neurons.     

Synaptic mechanisms of the action of subcortical formations on motoneurons in cat facial nerve

Characteristics of the synaptic processes produced by stimulating the head of the caudate nucleus, theglocus pallidus, and the central amygaloid nucleus were investigated in motoneurons of the facial nerve during acute experiments on cats using intracellular recording techniques. It was found that stimulating the first two of these structures causes polysynaptic activation, while both mono- and polysynaptic excitation of facial nerve motoneurons are produced by stimulation of the central amygdaloid nucleus.L. A. Orbeli Institute of Physiology, Academy of Sciences of the Armenian SSR, Erevan. Translated from Neirofiziologiya, Vol. 17, No. 6, pp. 800–809, November–December, 1985.     

The Regional Distribution and Chromatographic Characterisation of Neurotensin-Like Immunoreactivity in the Rat Central Nervous System

Abstract: Carboxy- and amino-terminal specific neurotensin antisera have been characterized and used to determine the nature of neurotensin-like immunoreactivity in the rat central nervous system. Using these antisera, together with the separation of neurotensin-like immunoreactivity on reversephase HPLC columns, it is clear that the majority of rat central nervous system neurotensin-like immunoreactivity is indistinguishable from the synthetic tridecapeptide. However, smaller amounts of carboxy- and amino-terminal neurotensin-like immunoreactivity were detected, which may correspond to carboxy- and amino-terminal fragments of neurotensin. In addition, using the amino-terminal directed neurotensin antiserum, a detailed distribution of neurotensin-like immunoreactivity in the rat central nervous system is described. Highest amounts were found in the hypothalamus, central amygdaloid nucleus, bed nucleus of the stria terminalis and the substantia gelatinosa of the spinal cord and of the trigeminal region.     

Wiring and Volume Transmission in Rat Amygdala. Implications for Fear and Anxiety

The amygdala plays a key role in anxiety. Information from the environment reaches the amygdaloid basolateral nucleus and after its processing is relayed to the amygdaloid central nucleus where a proper anxiogenic response is implemented. Experimental evidence indicates that in this information transfer a GABAergic interface controls the trafficking of impulses between the two nuclei. Recent work indicates that interneuronal communication can take place by classical synaptic transmission (wiring transmission) and by volume transmission in which the neurotransmitter diffuses and flows through the extracellular space from its site of release and binds to extrasynaptic receptors at various distances from the source. Based on evidence from our laboratory the concept is introduced that neurotransmitters in the amygdala can modulate anxiety involving changes in fear learning and memories by effects on receptor mosaics in the fear circuits through wiring and volume transmission modes of communication. Special issue article in honor of Dr. Ricardo Tapia.     

雌激素Beta受体在大鼠脑内表达的免疫组化定位研究

为了探讨雌激素作用于神经系统的机理,采用硫酸镍铵增强显色的免疫组化SP法研究了新的雌激素受体（ER－β）在成年雌雄大鼠脑内的分布。研究证实ER－β免疫阳性物质主要位于神经元的细胞核内,但在个别脑区也可在胞浆甚至突起内检测到。最强的ER－β免疫阳性信号见于前嗅核、大脑皮质、小脑浦肯野细胞、斜角带垂直部、蓝斑和三叉神经运动核等部位;中等强度的染色见于隔内侧核、杏仁外侧核、黑质、中央灰质等部位;较弱的阳性反应见于下丘脑与杏仁复合体的部分核团。在一些部位还存在表达水平甚至细胞内定位模式的性别差异,如前庭上核内的表达只见于雌性;雄性大鼠三叉神经运动核内ER－β蛋白主要表达于胞浆内,细胞核为阴性;而在雌性大鼠该部位ER－β蛋白主要位于细胞核等。以上结果表明ER－β蛋白在大鼠脑内分布广泛并具有一定的性别差异,在与学习记忆有关的脑区如大脑皮质和基底前脑内有很高的表达,提示在脑组织内雌激素可能通过ER－β这一新的信号途径发挥多种重要的调控作用,如学习记忆等。     

Autoradiographic distribution of 125I calcitonin gene-related peptide binding sites in the rat central nervous system

Using autoradiographic method and 125I-Tyro rat CGRP as a ligand, receptor binding sites were demonstrated in the rat central nervous system. Saturation studies and Scatchard analysis of CGRP-binding to slide mounted tissue sections containing primarily cerebellum showed a single class of receptors with a dissociation constant of 0.96 nM and a Bmax of 76.4 fmol/mg protein. 125I-Tyro rat CGRP binding sites were demonstrated throughout the rat central nervous system. Dense binding was observed in the telencephalon (medial prefrontal, insular and outer layers of the temporal cortex, nucleus accumbens, fundus striatum, central and inferior lateral amygdaloid nuclei, most caudal caudate putamen, organum vasculosum laminae terminalis, subfornical organ), the diencephalon (anterior hypothalamic, suprachiasmatic, arcuate, paraventricular, dorsomedial, periventricular, reuniens, rhomboid, lateral thalamic pretectalis and habenula nuclei, zona incerta), in the mesencephalon (superficial layers of the superior colliculus, central nucleus of the geniculate body, inferior colliculus, nucleus of the fifth nerve, locus coeruleus, nucleus of the mesencephalic tract, the dorsal tegmental nucleus, superior olive), in the molecular layer of the cerebellum, in the medulla oblongata (inferior olive, nucleus tractus solitarii, nucleus commissuralis, nuclei of the tenth and twelfth nerves, the prepositus hypoglossal and the gracilis nuclei, dorsomedial part of the spinal trigeminal tract), in the dorsal gray matter of the spinal cord (laminae I-VI) and the confines of the central canal. Moderate receptor densities were found in the septal area, the "head" of the anterior caudate nucleus, medial amygdaloid and bed nucleus of the stria terminalis, the pyramidal layers of the hippocampus and dentate gyri, medial preoptic area, ventromedial nucleus, lateral hypothalamic and ventrolateral thalamic area, central gray, reticular part of the substantia nigra, parvocellular reticular nucleus. Purkinje cell layer of the cerebellum, nucleus of the spinal trigeminal tract and gracile fasciculus of the spinal cord. The discrete distribution of CGRP-like binding sites in a variety of sensory systems of the brain and spinal cord as well as in thalamic and hypothalamic areas suggests a widespread involvement of CGRP in a variety of brain functions.     

Acetylcholinesterase enzyme localization in the amygdala: a comparative histochemical and ultrastructural study

The distribution of acetylcholinesterase enzyme was studied in the amygdala of some rodents, subprimates and several primates. The cytoarchitecture of the amygdala has presented various problems to anatomists, including the question as to how many nuclear groups and subgroups should be identified. Among the mammals examined, the arrangement of the amygdaloid nuclei is remarkably uniform and no clear phylogenetic trend can be recognised. Although there are minor differences, there seems to be a general similarity between most mammals examined in so far as the distribution of cholinesterase is concerned. The staining is less intense in the brains of the monkeys examined. The sole exception to the rule, that cholinesterase distribution is slightly different from nucleus to nucleus in different animals, is the magnocellular part of the basal nucleus. This amygdaloid nucleus stains quite strongly in all animals examined. From these findings, and those of others studying the distribution of choline acetyltransferase, it was concluded that the basal amygdaloid nucleus is cholinergic and possible cholinoceptive. The ultrastructural investigations appear to confirm this point. This is particularly applicable to the magnocellular part of the basal amygdaloid nucleus.     

Corticosteroid receptor-mediated mechanisms in the amygdala regulate anxiety and colonic sensitivity

Our previous studies have shown that stereotaxic implantation of corticosterone (Cort) onto the central amygdaloid nucleus increases both anxiety and colonic sensitivity. The goal of this study was to examine the relative importance of amygdaloid glucocorticoid (GR) and mineralocorticoid receptor (MR)-mediated mechanisms in the induction of anxiety and colonic hypersensitivity. In male Fischer 344 rats, Cort or cholesterol micropellets were stereotaxically implanted bilaterally at the dorsal boundary of the central amygdaloid nucleus either alone or in combination with a GR antagonist, mifepristone, or a MR antagonist, spironolactone. Anxiety was assessed on the elevated plus maze and quantified as the percentage of time spent in open arm exploration. Colonic sensitivity was measured by recording a visceromotor response, the number of abdominal muscle contractions in response to colorectal distension. In Cort-implanted rats there was a significant reduction in the percentage of time spent in the open arms of the elevated plus maze compared with cholesterol controls, indicating increased anxiety. Furthermore, colonic hypersensitivity was observed in response to colorectal distension compared with rats with cholesterol implants. In rats with Cort implants combined with either a GR or MR antagonist, there was a significant inhibition of anxiety and colonic hypersensitivity. Our data suggest that both GR and MR play a critical role in Cort-induced anxiety and colonic hypersensitivity.     

Topical organization of the projections to the putamen from the nuclei of the amygdaloid body in the cat

The investigation has been performed on the cat by means of the retrograde axonal transport of horseradish peroxidase method and luminescent markers. To the putamen along its rostro-caudal length and to all the segments projection fibers get only from the neurons of the basal nucleus of the amygdaloid body, greater number of the neurons projecting to the antero-ventral parts of the putamen than to the posterior ones. The problem on likeness in organization of the projections of the amygdaloid body and the caudate nucleus is discussed.     

The amygdala of the cat: A golgi study

Summary The amygdaloid complex in the cat was studied in a series of Golgi preparations. Both the lateral and the basal nucleus are composed of the same two cell types, one of which (type P) resembles the pyramidal and the other (type S) the stellate neuron of the cortex. The cortical nucleus can be divided into three layers (I, II, and III–IV) which are made up of cells similar to those in the periamygdaloid cortex. In addition, there are sufficient differences in the organization of these layers to justify a subdivision of the cortical nucleus into lateral and medial parts. The dendrites of neurons in the medial part of the central nucleus, the medial nucleus and the anterior amygdaloid area undergo less branching and carry fewer spines than those of the type P cell. The neurons in the nucleus of the lateral olfactory tract are all of the pyramidal or modified pyramidal type. These findings are discussed in relation to those of previous investigators who employed the Nissl and Golgi methods.This investigation was supported by the Medical Research Council of Canada, Grant M.T. 870. The author wishes to thank Miss Elizabeth Korzeniowski for her technical assistance.     

In vitro autoradiographic localization of vasoactive intestinal peptide (VIP) binding sites in the rat central nervous system

This paper describes the autoradiographic distribution of VIP binding sites in the rat central nervous system using monoiodinated ¹²³I-labeled VIP. High densities of VIP binding sites are observed in the granular layer of the dorsal dentate gyrus of the hippocampus, the basolateral amygdaloid nucleus, the dorsolateral and median geniculate nuclei of the thalamus as well as in the ventral part of the hypothalamic dorsomedial nucleus.     

Distribution and origin of vasoactive intestinal polypeptide-like immunoreactive fibers in the central amygdaloid nucleus of the rat: an immunocytochemical analysis

We studied the distribution of vasoactive intestinal polypeptide-like immunoreactive (VIPLI) fibers in the central amygdaloid (AC) nucleus of the rat, using indirect immunofluorescence and the origins of such fibers using a combination of retrograde tracing with immunocytochemistry. VIPLI fibers formed a dense fiber plexus in the lateral subdivision of the AC nucleus, but other subdivisions showed little immunoreactivity. Destruction of the supramammillary (SuM) region and the adjacent lateral hypothalamus, both of which contained a group of VIPLI neurons, resulted in the marked reduction of VIPLI fibers in the ipsilateral AC nucleus, indicating that many of the fibers in the AC nucleus originate from these two areas. This assumption was supported by the finding that injection of fast blue dye into the AC nucleus labeled the VIPLI neurons in the SuM region and lateral hypothalamus.     

Distribution of FMRFamide-like immunoreactivity in the central nervous system of the Formosan monkey (Macaca cyclopsis)

The distribution of FMRFamide-like immunoreactivity in the central nervous system of the Formosan monkey (Macaca cyclopsis) was investigated employing immunohistochemical techniques. FMRFamide-containing cells were found to be widely distributed throughout the forebrain. Principal densities of FMRFamide neuronal perikarya were observed in the following areas: the amygdaloid complex, the olfactory tubercle, the cerebral cortex, the basal ganglia, the septum, the caudate-putamen and the arcuate nucleus. A large number of immunoreactive fibers were observed in areas ranging from the cerebral cortex to the spinal cord, and were noted in the following locations: the preoptic area, the tuberal and posterior hypothalamic areas, the bed nucleus of the stria terminalis, the nuclei of the spinal trigeminal nerve, the hypoglossal nucleus, the nucleus of the solitary tract, and the dorsal horn of the spinal cord. The results generally parallel those described in the rat and guinea pig.     

大鼠脑内代谢型谷氨酸受体5亚型(mGluR5)定位分布的免疫细胞化学研究

本研究用免疫细胞化学技术观察了大鼠脑内参与兴奋性突触传递的代谢型谷氨酸受体5亚型(mGluR5)的精确定位分布.mGluR5阳性浓染的神经元胞体和纤维密集地分布于大脑皮质浅层、嗅球、伏核、尾壳核、前脑基底部、隔区、苍白球、腹侧苍白球、海马CA1和CA2区、下丘中央核、被盖背侧核和三叉神经脊束核尾侧亚核浅层;淡染而稀疏的mGluR5阳性神经元胞体和纤维见于屏状核、终纹床核、杏仁中央核、丘脑部分核团、上丘浅灰质层、外侧丘系背侧核和延髓中央灰质.     

Distribution of somatostatinlike immunoreactivity in the brain of the little brown bat (Myotis lucifugus)

The distribution of somatostatinlike immunoreactive (SLI) perikarya, axons, and terminals was mapped in subcortical areas of the brain of the little brown bat, Myotis lucifugus, using light microscopic immunocytochemistry. A preponderance of immunoreactivity was localized in reticular, limbic, and hypothalamic areas including: 1) in the forebrain: the bed nucleus of the stria terminalis; lateral preoptic, dorsal, anterior, lateral and posterior hypothalamic areas; amygdaloid, periventricular, arcuate, supraoptic, suprachiasmatic, ventromedial, dorsomedial, paraventricular, lateral and medial mammillary, and lateral septal nuclei; the nucleus of the diagonal band of Broca and nucleus accumbens septi; 2) in the midbrain: the periaqueductal gray, interpeduncular, dorsal and ventral tegmental, pretectal, and Edinger-Westphal nuclei; and 3) in the hindbrain: the superior central and parabrachial nuclei, nucleus incertus, locus coeruleus, and nucleus reticularis gigantocellularis. Other areas containing SLI included the striatum (caudate nucleus and putamen), zona incerta, infundibulum, supramammillary and premammillary nuclei, medial and dorsal lateral geniculate nuclei, entopeduncular nucleus, lateral habenular nucleus, central medial thalamic nucleus, central tegmental field, linear and dorsal raphe nuclei, nucleus of Darkschewitsch, superior and inferior colliculi, nucleus ruber, substantia nigra, mesencephalic nucleus of V, inferior olivary nucleus, inferior central nucleus, nucleus prepositus, and deep cerebellar nuclei. While these results were similar in some respects to those previously reported in rodents, they also provided interesting contrasts.