17 research outputs found

    Optical Control of Metabotropic Glutamate Receptors

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    G-protein coupled receptors (GPCRs), the largest family of membrane signaling proteins, respond to neurotransmitters, hormones and small environmental molecules. The neuronal function of many GPCRs has been difficult to resolve because of an inability to gate them with subtype-specificity, spatial precision, speed and reversibility. To address this, we developed an approach for opto-chemical engineering native GPCRs. We applied this to the metabotropic glutamate receptors (mGluRs) to generate light-agonized and light-antagonized ā€œLimGluRsā€. The light-agonized ā€œLimGluR2ā€, on which we focused, is fast, bistable, and supports multiple rounds of on/off switching. Light gates two of the primary neuronal functions of mGluR2: suppression of excitability and inhibition of neurotransmitter release. The light-antagonized ā€œLimGluR2blockā€ can be used to manipulate negative feedback of synaptically released glutamate on transmitter release. We generalize the optical control to two additional family members: mGluR3 and 6. The system works in rodent brain slice and in zebrafish in vivo, where we find that mGluR2 modulates the threshold for escape behavior. These light-gated mGluRs pave the way for determining the roles of mGluRs in synaptic plasticity, memory and disease

    Fig 8 1of2

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    All the data in Figure 8, part 1 of

    Data from: Extraocular motoneuron pools develop along a dorsoventral axis in zebrafish, Danio rerio

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    Both spatial and temporal cues determine the fate of immature neurons. A major challenge at the interface of developmental and systems neuroscience is to relate this spatiotemporal trajectory of maturation to circuitā€level functional organization. This study examined the development of two extraocular motor nuclei (nIII and nIV), structures in which a motoneuron's identity, or choice of muscle partner, defines its behavioral role. We used retroā€orbital dye fills, in combination with fluorescent markers for motoneuron location and birthdate, to probe spatial and temporal organization of the oculomotor (nIII) and trochlear (nIV) nuclei in the larval zebrafish. We describe a dorsoventral organization of the four nIII motoneuron pools, in which inferior and medial rectus motoneurons occupy dorsal nIII, while inferior oblique and superior rectus motoneurons occupy distinct divisions of ventral nIII. Dorsal nIII motoneurons are, moreover, born before motoneurons of ventral nIII and nIV. The order of neurogenesis can therefore account for the dorsoventral organization of nIII and may play a primary role in determining motoneuron identity. We propose that the temporal development of extraocular motoneurons plays a key role in assembling a functional oculomotor circuit

    Otolith size and the vestibulo-ocular reflex of larvae of white seabass Atractoscion nobilis at high pCO2

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    We investigated vestibular function and otolith size (OS) in larvae of white seabass Atractoscion nobilis exposed to high partial pressure of CO2 (pCO2). The context for our study is the increasing concentration of CO2 in seawater that is causing ocean acidification (OA). The utricular otoliths are aragonitic structures in the inner ear of fish that act to detect orientation and acceleration. Stimulation of the utricular otoliths during head movement results in a behavioral response called the vestibulo-ocular reflex (VOR). The VOR is a compensatory eye rotation that serves to maintain a stable image during movement. VOR is characterized by gain (ratio of eye amplitude to head amplitude) and phase shift (temporal synchrony). We hypothesized that elevated pCO2 would increase OS and affect the VOR. We found that the sagittae and lapilli of young larvae reared at 2500 Āµatm pCO2 (treatment) were 14 to 20% and 37 to 39% larger in area, respectively, than those of larvae reared at 400 Āµatm pCO2 (control). The mean gain of treatment larvae (0.39 +/- 0.05, n = 28) was not statistically different from that of control larvae (0.30 +/- 0.03, n = 20), although there was a tendency for treatment larvae to have a larger gain. Phase shift was unchanged. Our lack of detection of a significant effect of elevated pCO2 on the VOR may be a result of the low turbulence conditions of the experiments, large natural variation in otolith size, calibration of the VOR or mechanism of acid?base regulation of white seabass larvae

    14dpf boundaries

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    Data that describes the boundaries of 14dpf fish. No associated figure

    Fig 7 2 of 3

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    All the data in Figure 7, part 2 of

    Fig 6

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    All the data in Figure

    Fig 6-7

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    Data found in BOTH figures 6-7 (the SR cells

    Fig 3

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    Raw data associated with Figure
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