Optical imaging of parallel fiber activation in the rat cerebellar cortex: Spatial effects of excitatory amino acids

Elias, Stephen A.; Yae, H.; Ebner, Timothy J.

doi:10.1016/0306-4522(93)90528-n

Cited by 50 publications

(13 citation statements)

References 34 publications

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“…The evoked increases of CBF were larger OnB than OffB, but there was a definite CBF increase at both recording sites, though there are no excitatory neural structures perpendicular to the PF beam. A similar result was reported in an optical imaging study of voltage-sensitive dyes, which showed that small blood vessels perpendicular to the PF beam, extending for 500-600 pm, dilated in response to PF stimulation (29) (4). Further studies will be needed to address this issue and to examine the (21), which contain mainly non-NMDA receptor channels in the postsynaptic membrane (22,23).…”

Section: Discussionmentioning

confidence: 61%

Importance of nitric oxide for local increases of blood flow in rat cerebellar cortex during electrical stimulation.

Akgören

Fabricius

Lauritzen

1994

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

124

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The endothellum-derived relaxing factor, probably nitric oxide (NO), is a potent vasodilator that regulates the vascular tone in several vascular beds, inclu the brain. We explored the posibi that NO might be of importance for the increase of cerebral blood flow (CBF) a ited with activity of the well-efined neuronal circuits of the rat cerebellar cortex. Laser-loppler fiownry was used to measure increases of cerebellar blood flow evoked by trains of electrical stimulations of the dorsal surface. (25)(26)(27). Local NO synthesis from pre-and postsynaptic sources might therefore influence the microcirculation during periods of neuronal activation. This idea was tested using a specific, irreversible inhibitor of the constitutive form of NOS, NO-nitro-L-arginine (NOLAG), and specific antagonists of NMDA and non-NMDA receptors. Our study indicates that physiological increases of CBF associated with synaptic activity in neuronal networks are partly dependent on neuronal synthesis of NO. MATERIALS AND METHODSFifty-three male Wistar rats (300-350 g) were anesthetized with halothane (Vapor; Drliger) (4% induction, 1.5% during surgery, and 0.7% maintenance) in 30%6 02/70%6 N20. Catheters were inserted in a femoral artery and a femoral vein, and the trachea was cannulated. After relaxation with 5-15 mg of suxamethonium i.p., rats were ventilated with a volume respirator and placed in a headholder, and the occipital bone and the dura were removed over the cerebellar cortex. The craniotomy site was continuously superfused with artificial cerebrospinal fluid (CSF) at 37C, aerated with 95% 02/5% CO2 (composition in mM: NaCl, 120.00; KCl, 2.8; NaHCO3, 22.00; CaCl2, 1.45; Na2HPO4, 1.00; MgCl2, 0.876 (OffB). The experimental design is depicted in Fig. 1. tTo whom reprint requests should be addressed at:

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Section: Discussionmentioning

confidence: 61%

Importance of nitric oxide for local increases of blood flow in rat cerebellar cortex during electrical stimulation.

Akgören

Fabricius

Lauritzen

1994

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

124

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“…However, the signals employed by these methods mainly rely on neuronal excitation. Apart from a few reports of successful imaging of inhibitory circuit activity though the use of voltage-sensitive dyes (Horikawa et al, 1996;Cohen and Yarom, 2000;Derdikman et al, 2003), autofluorescence (Ebner et al, 2005), pH indicators (Elias et al, 1993) and organic Cl − indicator dyes (Isomura et al, 2003), synaptic inhibition has largely remained invisible even though inhibition contributes fundamentally to neuronal computation.…”

Section: Introductionmentioning

confidence: 99%

Imaging synaptic inhibition in transgenic mice expressing the chloride indicator, Clomeleon

et al. 2006

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“…1 C and D). There, electrical stimuli applied to the pial surface of the preparations gave rise to depolarizing voltage signals that spread in beam-like structures along the parallel fibers (16,17). All signals were abolished in 1 i,M tetrodotoxin (n = 3; Fig.…”

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confidence: 99%

Signal transmission in the parallel fiber-Purkinje cell system visualized by high-resolution imaging.

Vranesic¹,

Iijima²,

Ichikawa³

et al. 1994

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

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We investigated the synaptic transmission in the parallel fiber-PurkinJe cell system at high spatio-temporal resolution by using voltage-sensitive dyes and an imaging system. In rat cerebellar slices, cut in the frontal plane or in a plane of the cerebellar surface, local electrical stimulation induced volleys of action potentials in the parallel fibers; subsequent postsynaptic responses from Purkiaje cells were observed along the volleys' entire trajectories. Furthermore, the formation of an ordered spatial gradient in parallel fiber conduction velocity across the depth of the molecular layer during postnatal development was observed. In preparations of adult, but not of immature rats, the conduction velocity of parallel fibers in the deep molecular layer was faster than in its more superficial regions. Our observations demonstrate that parallel fibers can mediate Purkinje cell excitation effectively and over considerable distances in a well-organized spatiotemporal manner, thus supporting the classical view of the physiological role assigned to the parallel fibers.The mossy fiber input to the cerebellar cortex is relayed via the granule cells to the Purkinje cells, each of which receives well over 100,000 excitatory synaptic inputs from granule cells. The majority of these contacts are formed with the parallel fibers-i.e., the branches of granule cell axons that run in parallel to the cerebellar surface. A smaller number of synaptic contacts are formed with the vertically ascending portions of the granule cell axons before they bifurcate and give rise to the actual parallel fibers (1, 2). The classical view ofthe functional organization ofthe cerebellar cortex is based on the effectiveness of signal transmission at the parallel fiber-Purkinje cell synapses (3-10) along activated beams of parallel fibers. The pivotal role of signal transmission at these synapses has been questioned, based on the argument that the strongest and best synchronized synaptic input to the Purkinje cells is provided by the synapses formed with the ascending granule cell axons (2,11,12). In this picture, local mossy fiber inputs are processed by the Purkinje cells in the immediate neighborhood of that input. By using voltagesensitive dyes (13,14) and an optical recording system (15), we imaged the spread of action potential volleys in the parallel fibers. Subsequent postsynaptic responses from Purkinje cells were observed along the volleys' entire trajectories. In preparations of adult rats, the conduction velocity of parallel fibers in the deep molecular layer was faster than in its more superficial regions. Our observations demonstrate that parallel fibers can mediate Purkinje cell excitation effectively and over considerable distances in a well-organized spatio-temporal manner whose characteristics are adjusted during postnatal development. Our observations support the classical view ofthe physiological role assigned to the parallel fibers (3-10).MATERIALS AND METHODS Cerebellar Slices and Recording Setup. Wistar rats (eithe...

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Optical imaging of parallel fiber activation in the rat cerebellar cortex: Spatial effects of excitatory amino acids

Cited by 50 publications

References 34 publications

Importance of nitric oxide for local increases of blood flow in rat cerebellar cortex during electrical stimulation.

Importance of nitric oxide for local increases of blood flow in rat cerebellar cortex during electrical stimulation.

Imaging synaptic inhibition in transgenic mice expressing the chloride indicator, Clomeleon

Signal transmission in the parallel fiber-Purkinje cell system visualized by high-resolution imaging.

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