Local circuitry in the anterior caudal lobe of the mormyrid cerebellum: Intracellular recording and labelingZhang, Yueping; Han, Phil F.; Han, Victor Z.
doi: 10.1002/cne.21750pmid: N/A
Sagittal view of a Purkinje cell with symmetric dendritic tree from the anterior caudal lobe of the cerebellum of a mormyrid fish (Gnathonemus petersii). The cell was filled with neurobiotin in an in vitro slice preparation and tracer was revealed with red fluorescent dye. Nissl counterstaining is shown in green. The cell was photographed from a slice of 200 μm using a confocal laser scanning microscope. The cell body is located in the anterior border with the eminentia granularis anterior (upper right), and the axon was cut, probably projecting to the brainstem (for details see text). The dendritic tree is planar, extending for 500x700 μm in the sagittal plane, but only for 110 μm (optical thickness) medio‐laterally. Two smooth primary dendrites arise from the soma and give off secondary and tertiary branches irregularly in the molecular region. The dendrites become thinner and more spiny as they extend further from the cell body. J. Comp. Neurol. 509:1–22, 2008. © 2008 Wiley‐Liss, Inc.
Local circuitry in the anterior caudal lobe of the mormyrid cerebellum: A study of intracellular recording and labelingZhang, Yueping; Han, Phil F.; Han, Victor Z.
doi: 10.1002/cne.21682pmid: 18418897
The caudal lobe of the mormyrid cerebellum includes the anterior portion, which is associated with the lateral line and eighth nerve senses, and the posterior portion, which is associated with the electrosense. This study examines the physiology and morphology of cells in the anterior portion in slice preparations. Two subtypes of Purkinje cells, efferent cells and stellate cells, are described. Multipolar Purkinje cells are located in the central region of the lobe, with large, multipolar, spiny dendrites and locally ending axons. Small Purkinje cells are located along its anterior border with the eminentia granularis anterior (EGa), with spiny dendrites in the molecular region. Axons of some small Purkinje cells end locally, whereas axons of other such cells are cut at the surface of the slices, suggesting that they project outside the lobe. Efferent cells are also distributed along the border with EGa. These cells have thin, smooth dendrites in the molecular region, and their axons are cut at the sliced surface. Stellate cells have thin, smooth dendrites and locally terminating axons. Physiologically, all types of cells respond to parallel fiber activation, but only multipolar Purkinje cells showed characteristic all‐or‐none climbing fiber responses. Although the majority of Purkinje cells fire a single type of spikes at resting level, a subset of small Purkinje cells fire small, narrow and large, broad spikes. Thus, the anterior caudal lobe of the mormyrid cerebellum is different from the mammalian cerebellum in having different subtypes of Purkinje cells and local termination of many Purkinje cell axons. J. Comp. Neurol. 509:1–22, 2008. © 2008 Wiley‐Liss, Inc.
Ion transport peptide splice forms in central and peripheral neurons throughout postembryogenesis of Drosophila melanogasterDircksen, Heinrich; Tesfai, Lily Kahsai; Albus, Christina; Nässel, Dick R.
doi: 10.1002/cne.21715pmid: 18418898
Ion transport peptides (ITPs) belong to a large arthropod neuropeptide family including crustacean hyperglycaemic hormones and are antidiuretic hormones in locusts. Because long and short ITP isoforms are generated by alternative splicing from a single gene in locusts and moths, we investigated whether similarly spliced gene products occur in the nervous system of Drosophila melanogaster throughout postembryogenesis. The itp gene CG13586 was reanalyzed, and we found three instead of the two previously annotated alternatively spliced mRNAs. These give rise to three different neuropeptides, two long C‐terminally carboxylated isoforms (DrmITPL1 and DrmITPL2, both 87 amino acids) and one short amidated DrmITP (73 amino acids), which were partially identified biochemically. Immunocytochemistry and in situ hybridization reveal nine larval and 14 adult identified neurons: four pars lateralis neurosecretory neurons, three hindgut‐innervating neurons in abdominal ganglia, and a stage‐specific number of interneurons and peripheral bipolar neurons. The neurosecretory neurons persist throughout postembryogenesis, form release sites in corpora cardiaca, and invade corpora allata. One type of ITP‐expressing interneuron exists only in the larval and prepupal subesophageal ganglia, whereas three types of interneurons in the adult brain arise in late pupae and invade circumscribed neuropils in superior median and lateral brain areas. One peripheral bipolar and putative sensory neuron type occurs in the larval, pupal, and adult preterminal abdominal segments. Although the neurosecretory neurons may release DrmITP and DrmITPL2 into the haemolymph, possible physiological roles of the hindgut‐innervating and peripheral neurons as well as the interneurons are yet to be identified. J. Comp. Neurol. 509:23–41, 2008. © 2008 Wiley‐Liss, Inc.
Distribution and neurochemical identification of pancreatic afferents in the mouseFasanella, Kenneth E.; Christianson, Julie A.; Chanthaphavong, R. Savanh; Davis, Brian M.
doi: 10.1002/cne.21736pmid: 18418900
Dysfunction of primary afferents innervating the pancreas has been shown to contribute to the development of painful symptoms during acute and chronic pancreatitis. To investigate the distribution and neurochemical phenotype of pancreatic afferents, Alexa Fluor‐conjugated cholera toxin B (CTB) was injected into the pancreatic head (CTB‐488) and tail (CTB‐555) of adult male mice to label neurons retrogradely in both the dorsal root ganglia (DRG) and nodose ganglia (NG). The NG and DRG (T5–T13) were processed for fluorescent immunohistochemistry and visualized by using confocal microscopy. Spinal pancreatic afferents were observed from T5 to T13, with the greatest contribution coming from T9–T12. The pancreatic afferents were equally distributed between right and left spinal ganglia; however, the innervation from the left NG was significantly greater than from the right. For both spinal and vagal afferents there was significantly greater innervation of the pancreatic head relative to the tail. The total number of retrogradely labeled afferents in the nodose was very similar to the total number of DRG afferents. The neurochemical phenotype of DRG neurons was dominated by transient receptor potential vanilloid 1 (TRPV1)‐positive neurons (75%), GDNF family receptor alpha‐3 (GFRα3)‐positive neurons (67%), and calcitonin gene‐related peptide (CGRP)‐positive neurons(65%) neurons. In the NG, TRPV1‐, GFRα3‐, and CGRP‐positive neurons constituted only 35%, 1%, and 15% of labeled afferents, respectively. The disparity in peptide and receptor expression between pancreatic afferents in the NG and DRG suggests that even though they contribute a similar number of primary afferents to the pancreas, these two populations may differ in regard to their nociceptive properties and growth factor dependency. J. Comp. Neurol. 509:42–52, 2008. © 2008 Wiley‐Liss, Inc.
Glycine receptor‐mediated synaptic transmission regulates the maturation of ganglion cell synaptic connectivityXu, Hong‐Ping; Tian, Ning
doi: 10.1002/cne.21727pmid: 18425804
It is well documented that neuronal activity is required for the developmental segregation of retinal ganglion cell (RGC) synaptic connectivity with ON and OFF bipolar cells in mammalian retina. Our recent study showed that light deprivation preferentially blocked the developmental RGC dendritic redistribution from the center to sublamina a of the inner plexiform layer (IPL). To determine whether OFF signals in visual stimulation are required for OFF RGC dendritic development, the light‐evoked responses and dendritic stratification patterns of RGCs in Spastic mutant mice, in which the OFF signal transmission in the rod pathway is largely blocked due to a reduction of glycine receptor (GlyR) expression, were quantitatively studied at different ages and rearing conditions. The dendritic distribution in the IPL of these mice was indistinguishable from wildtype controls at the age of postnatal day (P)12. However, the adult Spastic mutants had altered RGC light‐evoked synaptic inputs from ON and OFF pathways, which could not be mimicked by pharmacologically blocking of glycinergic synaptic transmission on age‐matched wildtype animals. Spastic mutation also blocked the developmental redistribution of RGC dendrites from the center to sublamina a of the IPL, which mimicked the effects induced by light deprivation on wildtype animals. Moreover, light deprivation of the Spastic mutants had no additional impact on the RGC dendritic distribution and light response patterns. We interpret these results as that visual stimulation regulates the maturation of RGC synaptic activity and connectivity primarily through GlyR‐mediated synaptic transmission. J. Comp. Neurol. 509:53–71, 2008. © 2008 Wiley‐Liss, Inc.
Origins of endomorphin‐immunoreactive fibers and terminals in different columns of the periaqueductal gray in the ratChen, Tao; Hui, Rui; Wang, Xiao‐Ling; Zhang, Ting; Dong, Yuan‐Xiang; Li, Yun‐Qing
doi: 10.1002/cne.21728pmid: 18421704
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. J. Comp. Neurol. 509:72–87, 2008. © 2008 Wiley‐Liss, Inc.
Pigmented and nonpigmented ocelli in the brain vesicle of the ascidian larvaHorie, Takeo; Sakurai, Daisuke; Ohtsuki, Hisashi; Terakita, Akihisa; Shichida, Yoshinori; Usukura, Jiro; Kusakabe, Takehiro; Tsuda, Motoyuki
doi: 10.1002/cne.21733pmid: 18421706
The vertebrate‐type opsin, Ci‐opsin1, is localized in the outer segments of the photoreceptor cells of larvae of the ascidian Ciona intestinalis. The absorption spectrum of the photopigment reconstituted from Ci‐opsin1 and 11‐cis‐retinal suggested that the photopigment is responsible for photic behavior of the larvae. The structure and function of Ci‐opsin1‐positive photoreceptor cells were examined by immunohistochemistry, confocal microscopy, electron microscopy, laser ablation, and behavioral analysis. Ciona larvae have three morphologically distinct groups of photoreceptor cells in the brain vesicle. Group I and group II photoreceptor cells are associated with the ocellus pigment cell on the right side of the brain vesicle. The outer segments of the group I photoreceptor cells are regularly arranged inside the small cavity encircled by the cup‐shaped pigment cell. The outer segments of the group II photoreceptor cells are located outside the pigment cavity and exposed to the lumen of the brain vesicle. The outer segments of the group III photoreceptor cells are located near the otolith on the left ventral side of the brain vesicle. Thus, the brain vesicle of the ascidian larva has two ocelli: a ‘conventional’ pigmented ocellus containing the group I and group II photoreceptor cells and a novel nonpigmented ocellus solely consisting of the group III photoreceptor cells. Laser ablation experiments suggest that the pigmented ocellus is responsible for the photic swimming behavior. The nonpigmented ocellus might relate to later developmental or physiological events, such as metamorphosis, because Ci‐opsin1 immunoreactivity appears in the late larval stage and becomes intense just before the onset of metamorphosis. J. Comp. Neurol. 509:88–102, 2008. © 2008 Wiley‐Liss, Inc.
Immunolocalization of NMDA receptor subunit NR3B in selected structures in the rat forebrain, cerebellum, and lumbar spinal cordWee, Karen S.‐L.; Zhang, Yibin; Khanna, Sanjay; Low, Chian‐Ming
doi: 10.1002/cne.21747pmid: 18425811
N‐methyl‐D‐aspartate (NMDA) receptors have been implicated in many neurological disorders. Although NMDA receptors are best known for their high calcium permeability, the recently discovered NR3 subunits, NR3A and NR3B, have been shown to reduce the calcium permeability of the NMDA receptor. Thus, NR3 subunits may be important players in modulating synaptic plasticity in neurons. Although NR3B expression in the rodent and human brain has been studied, little is known about its distribution in different cell types. Here we used immunolabeling with a specific NR3B antibody together with antibodies against established neurochemical markers to determine the cellular and subcellular localization of NR3B. The nucleus was concurrently stained with NR3B immunolabeling to show that NR3B is widely expressed by many cells in each brain region. Our findings indicate that NR3B is widely expressed in the structures examined in the rat forebrain (hippocampus, cerebral cortex, caudoputamen, and nucleus accumbens), cerebellum, and lumbar sections of the spinal cord. Within these regions NR3B was found to be expressed in all the substructures of the hippocampus (CA1, CA3, dentate gyrus), the various layers of the cerebral cortex, projection neurons and interneurons of the striatum, different cell types of the cerebellum, and motor neurons of the spinal cord. Furthermore, when stained with NR1—the obligatory subunit responsible for forming functional NMDA receptors—the distribution of NR3B appears to be as ubiquitous as NR1. Taken together, our data suggest that there may be a population of NR3B‐containing NMDA receptors conferring new functional roles in the mammalian central nervous system. J. Comp. Neurol. 509:118–135, 2008. © 2008 Wiley‐Liss, Inc.