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Kondo, Hideki; Saleem, Kadharbatcha S.; Price, Joseph L.
doi: 10.1002/cne.20796pmid: 16304624
Previous anatomical studies indicate that the orbital and medial prefrontal cortex (OMPFC) of monkeys is organized into an “orbital” network, which appears to be related to feeding and reward, and a “medial” network, related to visceral control and emotion. In this study, we examined the connections of the orbital and medial prefrontal networks with the perirhinal (areas 35 and 36) and parahippocampal (areas TF and TH) cortex with anterograde and retrograde axonal tracers. The perirhinal cortex is reciprocally connected with orbital network areas Iapm, Iam, Ial, 13m, 13l, 12r, and 11l. In contrast, the parahippocampal cortex is reciprocally connected with the medial network, especially areas around the corpus callosum (areas 24a/b, caudal 32, and 25), and with area 11m. Projections from the parahippocampal cortex also extend to areas 10m, 10o, Iai, and rostral area 32, as well as to dorsolateral areas 9 and 46. In addition, both the perirhinal and parahippocampal cortex are reciprocally connected with areas that are intermediate between the orbital and medial networks (areas 13a, 13b, and 14c) and with the supracallosal area 24a′/b′. Outside the frontal cortex, the perirhinal cortex and the orbital prefrontal network are both interconnected with the ventral part of the temporal pole (TG), area TE and the ventral bank and fundus of the superior temporal sulcus (STS), and the dysgranular insula. In contrast, the parahippocampal cortex and the medial prefrontal network are connected with the dorsal TG, the rostral superior temporal gyrus (STG) and dorsal bank of STS, and the retrosplenial cortex. J. Comp. Neurol. 493:479–509, 2005. © 2005 Wiley‐Liss, Inc.
Sugiyo, Shinichi; Takemura, Motohide; Dubner, Ronald; Ren, Ke
doi: 10.1002/cne.20797pmid: 16304628
Recent studies have implicated a role for the trigeminal interpolaris/caudalis (Vi/Vc) transition zone in response to orofacial injury. Using combined neuronal tracing and Fos protein immunocytochemistry, we investigated functional connections between the Vi/Vc transition zone and rostral ventromedial medulla (RVM), a key structure in descending pain modulation. Rats were injected with a retrograde tracer, FluoroGold, into the RVM 7 days before injection of an inflammatory agent, complete Freund's adjuvant, into the masseter muscle and perfused at 2 hours postinflammation. A population of neurons in the ventral Vi/Vc overlapping with caudal ventrolateral medulla, and lamina V of the trigeminal subnucleus caudalis (Vc), exhibited FluoroGold/Fos double staining, suggesting the activation of the trigeminal‐RVM pathway after inflammation. No double‐labeled neurons were found in the dorsal Vi/Vc and laminae I–IV of Vc. Injection of an anterograde tracer, Phaseolus vulgaris leucoagglutinin, into the RVM resulted in labeling profiles overlapped with the region that showed FluoroGold/Fos double labeling, suggesting reciprocal connections between RVM and Vi/Vc. Lesions of Vc with a soma‐selective neurotoxin, ibotenic acid, significantly reduced inflammation‐induced Fos expression as well as the number of FluoroGold/Fos double‐labeled neurons in the ventral Vi/Vc (P < 0.05). Compared with control rats, lesions of the RVM (n = 6) or Vi/Vc (n = 6) with ibotenic acid led to the elimination or attenuation of masseter hyperalgesia/allodynia developed after masseter inflammation (P < 0.05–0.01). The present study demonstrates reciprocal connections between the ventral Vi/Vc transition zone and RVM. The Vi/Vc‐RVM pathway is activated after orofacial deep tissue injury and plays a critical role in facilitating orofacial hyperalgesia. J. Comp. Neurol. 493:510–523, 2005. © 2005 Wiley‐Liss, Inc.
Farrar, Christine E.; Huang, Christine S.; Clarke, Steven G.; Houser, Carolyn R.
doi: 10.1002/cne.20780pmid: 16304629
Recent studies have demonstrated that mice lacking protein L‐isoaspartate (D‐aspartate) O‐methyltransferase (Pcmt1−/− mice) have alterations in the insulin‐like growth factor‐I (IGF‐I) and insulin receptor pathways within the hippocampal formation as well as other brain regions. However, the cellular localization of these changes and whether the alterations might be associated with an increase in cell number within proliferative regions, such as the dentate gyrus, were unknown. In this study, stereological methods were used to demonstrate that these mice have an increased number of granule cells in the granule cell layer and hilus of the dentate gyrus. The higher number of granule cells was accompanied by a greater number of cells undergoing mitosis in the dentate gyrus, suggesting that an increase in neuronal cell proliferation occurs in this neurogenic zone of adult Pcmt1−/− mice. In support of this, increased doublecortin labeling of immature neurons was detected in the subgranular zone of the dentate gyrus. In addition, double immunofluorescence studies demonstrated that phosphorylated IGF‐I/insulin receptors in the subgranular zone were localized on immature neurons, suggesting that the increased activation of one or both of these receptors in Pcmt1−/− mice could contribute to the growth and survival of these cells. We propose that deficits in the repair of isoaspartyl protein damage leads to alterations in metabolic and growth‐receptor pathways, and that this model may be particularly relevant for studies of neurogenesis that is stimulated by cellular damage. J. Comp. Neurol. 493:524–537, 2005. © 2005 Wiley‐Liss, Inc.
Avendaño, Carlos; Machín, Raquel; Bermejo, Pedro E.; Lagares, Alfonso
doi: 10.1002/cne.20778pmid: 16304625
The volume, total neuron number, and number of GABA‐ and glycine‐expressing neurons in the sensory trigeminal nuclei of the adult rat were estimated by stereological methods. The mean volume is 1.38 ± 0.13 mm3 (mean ± SD) for the principal nucleus (Vp), 1.59 ± 0.06 for the n. oralis (Vo), 2.63 ± 0.34 for the n. interpolaris (Vip), and 3.73 ± 0.11 for the n. caudalis (Vc). The total neuron numbers are 31,900 ± 2,200 (Vp), 21,100 ± 3,300 (Vo), 61,600 ± 8,300 (Vip), and 159,100 ± 25,300 (Vc). Immunoreactive (‐ir) neurons were classified as strongly stained or weakly stained, depending on qualitative criteria, cross‐checked by a densitometric analysis. GABA‐ir cells are most abundant in Vc, in an increasing rostrocaudal gradient within the nucleus. Lower densities are found in Vip and Vp. The mean total number of strongly labeled GABA‐ir neurons ranges between 1,800 in Vp to 7,800 in Vip and 22,900 in Vc, and varies notably between subjects. Glycine‐ir neurons are more numerous and display more homogeneous densities in all nuclei. Strongly labeled Gly‐ir cells predominate in all nuclei, their total number ranging between 9,400 in Vp to 24,300 in Vip and 34,200 in Vc. A substantial fraction of immunolabeled neurons in all nuclei coexpress GABA and glycine. In general, all neurons strongly immunoreactive for GABA are small, while weakly GABA‐ir cells which coexpress Gly are larger. In Vc, one‐third of all neurons are immunoreactive: 16.6% of them are single‐labeled for GABA and 31.6% are single‐labeled for glycine. The remaining 51.8% express GABA and glycine in different combinations, with those showing strong double labeling accounting for 22.6%. J. Comp. Neurol. 493:538–553, 2005. © 2005 Wiley‐Liss, Inc.
Guadaño‐Ferraz, Ana; Viñuela, Angel; Oeding, Guillermo; Bernal, Juan; Rausell, Estrella
doi: 10.1002/cne.20774pmid: 16304627
RC3/neurogranin is a neuron‐specific calpacitin located in the cytoplasm and, especially, in dendrites and dendritic spines of cortical neurons, involved in many aspects of excitatory transmission and long‐term potentiation. We investigated RC3 expression in pyramidal cortical neurons and interneurons of the motor and somatosensory cortex of normal Macaca fascicularis by means of double immunofluorescence and with techniques that combine immunohistochemistry and radioactive in situ hybridization. We show that RC3 is expressed in virtually all pyramidal neurons and spiny stellate neurons of neocortical areas 4, 3b, 1, 2, 5, 7, and SII, but not in the majority of cortical interneurons. RC3 protein and mRNA are tightly colocalized with the α subunit of CaM kinase II and the 200‐kD, nonphosphorylated neurofilament, whereas they are absent from cells expressing the 27‐kD, vitamin D‐dependent calbindin and parvalbumin. In order to investigate possible activity‐dependent regulation of the expression of RC3, we compared these results with those obtained from monkeys subjected to chronic peripheral cutaneous denervation of the first finger. We found that the pattern of distribution of RC3 in motor and somatosensory cortices after nerve cut did not differ from normal. J. Comp. Neurol. 493:554–570, 2005. © 2005 Wiley‐Liss, Inc.
Shi, Lijun; Mao, Caiping; Thornton, Simon N.; Sun, Wanping; Wu, Jiawei; Yao, Jiaming; Xu, Zhice
doi: 10.1002/cne.20802pmid: 16304626
The renin‐angiotensin system plays an important role in cardiovascular control. Intracerebroventricular (i.c.v.) angiotensin (ANG) II causes a reliable pressor response in the fetus at 90% gestation. To determine the roles of brain AT1 and AT2 receptors in this response, the effects of the central AT1 and AT2 receptor antagonists losartan and PD123319 were investigated in chronically prepared near‐term ovine fetuses. Losartan at 0.5 mg/kg (i.c.v.) abolished central ANG II‐induced pressor responses. High‐dose losartan (5 mg/kg, i.c.v.) showed a potentiation of the pressor response to i.c.v. ANG II, accompanied by bradycardia. Associated with the pressor responses, c‐fos expression in the cardiovascular controlling areas was significantly different between the low and high doses of losartan. These areas included the subfornical organ, median preoptic nucleus, organum vasculosum of the lamina terminalis, and paraventricular nuclei in the forebrain, and the tractus solitarius nuclei, lateral parabrachial nuclei in the hindbrain. Low‐dose losartan markedly reduced c‐fos in these areas after i.c.v. ANG II, while the high‐dose losartan together with ANG II elicited a much stronger FOS‐immunoreactivity in these areas than that induced by i.c.v. ANG II alone. This is a novel finding, that c‐fos expression in the brain can be both activated and inhibited under the same condition. Central ANG II‐induced fetal pressor responses were not altered by PD123319 (0.8 mg/kg). These results indicate that i.c.v. losartan at a high and a low dose has strikingly different effects on central ANG II‐induced pressor responses in fetuses at late gestation, and that the AT1 mechanism plays an important role in fetal cardiovascular regulation. J. Comp. Neurol. 493:571–579, 2005. © 2005 Wiley‐Liss, Inc.
Klop, Esther Marije; Mouton, Leonora J.; Holstege, Gert
doi: 10.1002/cne.20777pmid: 16304630
The spinothalamic tract (STT), well known for its role in the relay of information about noxe, temperature, and crude touch, is usually associated with projections from lamina I, but spinothalamic neurons in other laminae have also been reported. In cat, no complete overview exists of the precise location and number of spinal cells that project to the thalamus. In the present study the laminar distribution of retrogradely labeled cells in all spinal segments (C1–Coc2) was investigated after large WGA‐HRP injections in the thalamus. The results show that this distribution of STT cells differed greatly between the different spinal segments. Quantitative analysis showed that there exist at least five separate clusters of spinothalamic neurons. Lamina I neurons in cluster A and lamina V neurons in cluster B are mainly found contralaterally throughout the length of the spinal cord. Cluster C neurons are located bilaterally in the ventrolateral part of laminae VI–VII and lamina VIII of the C1–C3 spinal cord. Cluster D neurons were found contralaterally in lamina VI in the C1–C2 segments, and cluster E neurons were located mainly contralaterally in the medial part of laminae VI–VII and lamina VIII of the lumbosacral cord. Most spinothalamic neurons are not located in the enlargements and most spinothalamic neurons are not located in lamina I, as suggested by several other authors. The location of the spinothalamic neurons shows remarkable similarities, but also differences, with the location of spino‐periaqueductal gray neurons. J. Comp. Neurol. 493:580–595, 2005. © 2005 Wiley‐Liss, Inc.
Kobayashi, Kimiko; Fukuoka, Tetsuo; Obata, Koichi; Yamanaka, Hiroki; Dai, Yi; Tokunaga, Atsushi; Noguchi, Koichi
doi: 10.1002/cne.20794pmid: 16304633
The transient receptor potential (TRP) superfamily of cation channels contains four temperature‐sensitive channels, named TRPV1–4, that are activated by heat stimuli from warm to that in the noxious range. Recently, two other members of this superfamily, TRPA1 and TRPM8, have been cloned and characterized as possible candidates for cold transducers in primary afferent neurons. Using in situ hybridization histochemistry and immunohistochemistry, we characterized the precise distribution of TRPA1, TRPM8, and TRPV1 mRNAs in the rat dorsal root ganglion (DRG) and trigeminal ganglion (TG) neurons. In the DRG, TRPM8 mRNA was not expressed in the TRPV1‐expressing neuronal population, whereas TRPA1 mRNA was only seen in some neurons in this population. Both A‐fiber and C‐fiber neurons expressed TRPM8, whereas TRPV1 was almost exclusively seen in C‐fiber neurons. All TRPM8‐expressing neurons also expressed TrkA, whereas the expression of TRPV1 and TRPA1 was independent of TrkA expression. None of these three TRP channels were coexpressed with TrkB or TrkC. The TRPM8‐expressing neurons were more abundant in the TG compared with the DRG, especially in the mandibular nerve region innervating the tongue. Our data suggest heterogeneity of TRPM8 and TRPA1 expression by subpopulations of primary afferent neurons, which may result in the difference of cold‐sensitive primary afferent neurons in sensitivity to chemicals such as menthol and capsaicin and nerve growth factor. J. Comp. Neurol. 493:596–606, 2005. © 2005 Wiley‐Liss, Inc.
Fu, Qiang; Kutz, Kimberly K.; Schmidt, Joshua J.; Hsu, Yun‐Wei A.; Messinger, Daniel I.; Cain, Shaun D.; de la Iglesia, Horacio O.; Christie, Andrew E.; Li, Lingjun
doi: 10.1002/cne.20773pmid: 16304631
Showing 1 to 10 of 10 Articles
In crustaceans, circulating hormones influence many physiological processes. Two neuroendocrine organs, the sinus gland (SG) and the pericardial organ (PO), are the sources of many of these compounds. As a first step in determining the roles played by hemolymph‐borne agents in the crab Cancer productus, we characterized the hormone complement of its SG and PO. We show via transmission electron microscopy that the nerve terminals making up each site possess dense‐core and/or electron‐lucent vesicles, suggesting diverse complements of bioactive molecules for both structures. By using immunohistochemistry, we show that small molecule transmitters, amines and peptides, are among the hormones present in these tissues, with many differentially distributed between the two sites (e.g., serotonin in the PO but not the SG). With several mass spectrometric (MS) methods, we identified many of the peptides responsible for the immunolabeling and surveyed the SG and PO for peptides for which no antibodies exist. By using MS, we characterized 39 known peptides [e.g., β‐pigment‐dispersing hormone (β‐PDH), crustacean cardioactive peptide, and red pigment‐concentrating hormone] and de novo sequenced 23 novel ones (e.g., a new β‐PDH isoform and the first B‐type allatostatins identified from a non‐insect species). Collectively, our results show that diverse and unique complements of hormones, including many previously unknown peptides, are present in the SG and PO of C. productus. Moreover, our study sets the stage for future biochemical and physiological studies of these molecules and ultimately the elucidation of the role(s) they play in hormonal control in C. productus. J. Comp. Neurol. 493:607–626, 2005. © 2005 Wiley‐Liss, Inc.