Expression of the vesicular glutamate transporters during development indicates the widespread corelease of multiple neurotransmitters

Boulland, Jean-Luc; Qureshi, Abdul Rashid; Seal, Rebecca P.; Rafiki, Amina; Gundersen, Vidar; Bergersen, Linda Hildegard; Fremeau, Robert T.; Edwards, Robert H.; Storm‐Mathisen, Jon; Chaudhry, Farrukh A.

doi:10.1002/cne.20354

Cited by 253 publications

(251 citation statements)

References 83 publications

(134 reference statements)

Supporting

Mentioning

225

Contrasting

Order By: Relevance

“…This finding is in agreement with previous anatomical studies (8,21), which could not demonstrate the presence of VGLUT1-3 in the neuromuscular junction. However, a recent study has shown that VGLUT3 is expressed in proximity to the endplates in skeletal muscles (27). At the moment, there is no explanation for the discrepancies between different studies.…”

Section: Discussionmentioning

confidence: 93%

Mammalian motor neurons corelease glutamate and acetylcholine at central synapses

Nishimaru

Restrepo

Ryge

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

220

201

View full text Add to dashboard Cite

Motor neurons (MNs) are the principal neurons in the mammalian spinal cord whose activities cause muscles to contract. In addition to their peripheral axons, MNs have central collaterals that contact inhibitory Renshaw cells and other MNs. Since its original discovery >60 years ago, it has been a general notion that acetylcholine is the only transmitter released from MN synapses both peripherally and centrally. Here, we show, using a multidisciplinary approach, that mammalian spinal MNs, in addition to acetylcholine, corelease glutamate to excite Renshaw cells and other MNs but not to excite muscles. Our study demonstrates that glutamate can be released as a functional neurotransmitter from mammalian MNs.synaptic transmission ͉ spinal cord M otor neurons (MNs) are the output neurons from the central nervous system. Their activity directly leads to muscle contraction. By the 1940s, it was generally accepted that MNs release acetylcholine (ACh) at the neuromuscular junction (1). Shortly thereafter, it was shown that ACh also is released from MNs' central axonal branches contacting Renshaw cells (RCs) (2). As was found at the neuromuscular junction, this transmission was shown to be nicotinic (3, 4). The collaterals contacting other MNs (5) are also thought to be mediated by ACh, although this has not been shown directly (6). Since these initial discoveries and after many later investigations, it has been a general dogma that mammalian MNs contain and release one neurotransmitter, ACh, both centrally and peripherally. It has been suggested recently, based on anatomical data, that MNs might contain glutamate as a neurotransmitter (7,8). There has been, however, no direct electrophysiological evidence to support this. Here, we examine this question directly by investigating the transmission in central and peripheral MN synapses (Fig. 1a). Materials and MethodsRecordings from RCs and MNs. All procedures followed Swedish federal guidelines for animal care. Postnatal heterozygote glutamic acid decarboxylase (GAD) 67-GFP mice [postnatal day (P) 0 to P4] were anaesthetized with isoflurane and eviscerated, and spinal cords were removed with ventral laminectomy, as described in ref. 9. The spinal cord was placed in a recording chamber perfused with oxygenated Ringer's solution (128 mM NaCl͞4.69 mM KCl͞25 mM NaHCO 3 ͞1.18 mM KH 2 PO 4 ͞1.25 mM MgSO 4 ͞2.5 mM CaCl 2 ͞22 mM glucose aerated with 5% CO 2 in O 2 ) at room temperature. Whole-cell tight-seal recording of RCs and MNs were performed with patch electrodes pulled from thick-walled borosilicate glass (o.d. of 1.5 mm, i.d. of 1.0 mm; Harvard Instruments) to a final resistance of 5-8 M⍀. The electrode tips were filled with 138 mM K-gluconate, 10 mM Hepes, 0.0001 mM CaCl 2 , 5 mM ATP-Mg, and 0.3 mM GTP-Li. After filling of the tip, the electrodes were back-filled with the same solution, and to label the recorded cell, Alexa Fluor dye (0.15-0.20%; Molecular Probes) or neurobiotin (1-2%) was diluted into the electrode solution. Cells were filled during recording. Signals wer...

show abstract

Section: Discussionmentioning

confidence: 93%

Mammalian motor neurons corelease glutamate and acetylcholine at central synapses

Nishimaru

Restrepo

Ryge

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

220

201

View full text Add to dashboard Cite

show abstract

“…Recent studies demonstrating VGluT-2 immunostaining in motoneuron collateral axons projecting to layer VII of the spinal cord (28,32) confirmed the lack of VGluT-2 and glutamatergic transmission in the cholinergic projections to the NMJ. Furthermore, studies on VGluT-3 expression at the skeletal muscle endplates gave contradictory results (33,34). The difficulty in demonstrating VGluT expression at the cholinergic synapses indicates that mechanisms responsible for the high concentration of glutamate at the NMJ still need to be clarified or their identification requires more sensitive investigation tools.…”

Section: Discussionmentioning

confidence: 99%

Glutamatergic reinnervation through peripheral nerve graft dictates assembly of glutamatergic synapses at rat skeletal muscle

Brunelli

Spano

Barlati

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Acetylcholine is the main neurotransmitter at the mammalian neuromuscular junction (NMJ) where nicotinic acetylcholine receptors mediate the signaling between nerve terminals and muscle fibers. We show that under glutamatergic transmission, rat NMJ switches from cholinergic type synapse to glutamatergic synapse. Connecting skeletal muscle to the lateral white matter of the spinal cord by grafting the distal stump of the transected motor nerve produced functional muscle reinnervation. The restored neuromuscular activity became resistant to common curare blockers but sensitive to the glutamate ␣-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist. Analysis of the regenerated nerve disclosed new glutamatergic axons and the disappearance of cholinergic fibers. Many axons belonged to the supraspinal neurons located in the red nucleus and the brainstem nuclei. Finally, the innervated muscle displayed high expression and clustering of ␣-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunits glutamate receptors 1 and 2. Our data suggest that supraspinal neurons can target skeletal muscle, which retains the plasticity to generate functional glutamatergic NMJ.glutamate ͉ neuromuscular junction ͉ red nucleus T raumatic paraplegia caused by spinal cord injury is still an irreversible condition. So far, there is no medical or surgical treatment capable of curing paraplegia. The CNS is ''nonpermissive'' for the advancement of injured axons because of an abundance of growth-inhibitory molecules in the myelin and the glial scar (1-3). In addition, there are no growth-promoting factors at the neuronal growth cone or at the somata. However, when peripheral nerves (PN) are directly grafted into the CNS, central axons can progress throughout the peripheral endoneural tubes, suggesting they can regenerate in an appropriate environment (4-7). The central fibers that are diverted into a nerve graft implanted within a healthy structure derive from neurons axotomized during the grafting procedure and not from uninjured neurons spared by nerve graft implantation (8). Regrowth ceases as soon as axons contact the CNS milieu again. Various studies have demonstrated that central axons can elongate within autologous PN grafted into the spinal cord and form functional synapses with skeletal muscles, leading to motor and sensory recovery (7, 9-11). Spinal cord neurons, as well as the midbrain and brainstem neurons that originate the rubrospinal, vestibulospinal, and reticulospinal tracts, are endowed with a high capability of axonal regeneration into PN transplants (12-15). Thus, in an attempt to bypass a spinal cord lesion by connecting descending motor fibers with skeletal muscles, muscular nerve branches were inserted into the severed lateral bundle of monkey spinal cord (11). The new connection produced muscle reinnervation and restored motor function. This result raised the possibility that the regrowth of axons descending from central noncholinergic neurons and cut during the grafting procedure could be re...

show abstract

“…In mammalian development, VGluT1 expression increases gradually after birth and predominates over the other isoforms in telencephalic regions. In contrast, VGluT2 is expressed at high levels shortly after birth and declines with age (Boulland et al, 2004;Nakamura et al, 2005). In the present study, we only investigated the changes in VGluT1-immunopositive synapse densities.…”

Section: Saturation Of Vglut1-and Vgat-immunopositive Synaptic Densitmentioning

confidence: 98%

Measurement of saturation processes in glutamatergic and GABAergic synapse densities during long-term development of cultured rat cortical networks

2013

View full text Add to dashboard Cite

The aim of this study was to clarify the saturation processes of excitatory and inhibitory synapse densities during the long-term development of cultured neuronal networks. For this purpose, we performed a long-term culture of rat cortical cells for 35 days in vitro (DIV). During this culture period, we labeled glutamatergic and GABAergic synapses separately using antibodies against vesicular glutamate transporter 1 (VGluT1) and vesicular transporter of -aminobutyric acid (VGAT). The densities and distributions of both types of synaptic terminals were measured simultaneously. Observations and subsequent measurements of immunofluorescence demonstrated that the densities of both types of antibody-labeled terminals increased gradually from 7 to 21-28 DIV. The densities did not show a further increase at 35 DIV and tended to become saturated.Triple staining with VGluT1, VGAT, and microtubule-associated protein 2 (MAP2) enabled analysis of the distribution of both types of synapses, and revealed that the densities of the two types of synaptic terminals on somata were not significantly different, but that glutamatergic synapses predominated on the dendrites during long-term culture.However, some neurons did not fall within this distribution, suggesting differences in synapse distribution on target neurons. The electrical activity also showed an initial increase and subsequent saturation of the firing rate and synchronized burst rate during long-term culture, and the number of days of culture to saturation from the initial increase followed the same pattern under this culture condition.

show abstract

Expression of the vesicular glutamate transporters during development indicates the widespread corelease of multiple neurotransmitters

Cited by 253 publications

References 83 publications

Mammalian motor neurons corelease glutamate and acetylcholine at central synapses

Mammalian motor neurons corelease glutamate and acetylcholine at central synapses

Glutamatergic reinnervation through peripheral nerve graft dictates assembly of glutamatergic synapses at rat skeletal muscle

Measurement of saturation processes in glutamatergic and GABAergic synapse densities during long-term development of cultured rat cortical networks

Contact Info

Product

Resources

About