July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
Ocular hypertension alters spiking behavior of neurons in the visual thalamus.
Author Affiliations & Notes
  • Matthew J Van Hook
    University of Nebraska Medical Center, Omaha, Nebraska, United States
  • Shan Fan
    University of Nebraska Medical Center, Omaha, Nebraska, United States
  • Lisa Reid
    University of Nebraska Medical Center, Omaha, Nebraska, United States
  • Toni Goeser
    University of Nebraska Medical Center, Omaha, Nebraska, United States
  • Jennie C. Smith
    University of Nebraska Medical Center, Omaha, Nebraska, United States
  • Deepta Abhay Ghate
    University of Nebraska Medical Center, Omaha, Nebraska, United States
  • Footnotes
    Commercial Relationships   Matthew Van Hook, None; Shan Fan, None; Lisa Reid, None; Toni Goeser, None; Jennie Smith, None; Deepta Ghate, None
  • Footnotes
    Support  BrightFocus Foundation grant G2017027, NIH grant GM110768.
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 5299. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Matthew J Van Hook, Shan Fan, Lisa Reid, Toni Goeser, Jennie C. Smith, Deepta Abhay Ghate; Ocular hypertension alters spiking behavior of neurons in the visual thalamus.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5299.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : Elevated eye pressure (ocular hypertension, OHT) causes optic nerve (ON) injury that leads to eventual dysfunction and degeneration of retinal ganglion cells (RGCs) in glaucoma. The goal of this study is to determine how early OHT affects the function of thalamocortical relay neurons (TC neurons) in the dorsal lateral geniculate nucleus (dLGN), a major brain nucleus receiving RGCs inputs in an experimental mouse model of OHT.

Methods : Bilateral anterior chamber injection of 10-micron polystyrene microbeads was used to induce a modest (~30% increase) and sustained OHT in 6-8 week-old mice (control = saline injection). Eye pressure was monitored with a TonoLab tonometer and experiments were performed at 5 and 8 weeks post-injection. TC neurons were targeted for whole-cell recordings in coronal dLGN slices using a K+-based pipette solution with neurobiotin. Post-recording, TC neurons were processed with fluorescent streptavidin and dendrites were analyzed with a Sholl analysis. Optical coherence tomography (OCT) was used to measure central retinal thickness. Data are mean±SD and significance was tested using a t-test.

Results : OHT TC cells were slightly depolarized relative to control (control: -81±5 mV, n=38; OHT: -75±3 mV, n=23; p<0.0001) and input resistance was elevated in OHT cells (Control: 328±86 MΩ; OHT: 443±91 MΩ; p<0.005). Depolarization with 500-ms current injections revealed that OHT TC cells fired more action potentials than controls (160 pA; control: 15.0±8.0; OHT: 23.6±6.2, p<0.005). This was reflected in a higher steady-state spike frequency in OHT (46±12 Hz vs 31±15 Hz in control, p<0.01). 5 weeks of OHT also led to a significant reduction in dendrite complexity. There was no detectable thinning of the inner retina measured by OCT at this time point. By 8 weeks OHT, TC neuron spiking was reduced, with TC neurons firing only 6.8±4.3 spikes (n=10). At this time point, input resistance (271±82 MΩ) and resting potential (-83.6±4.2 mV) appeared to recover to near control levels.

Conclusions : These findings indicate that OHT alters the membrane properties and excitability of neurons receiving input from retinal ganglion cells in the visual thalamus along a biphasic time course. The mechanisms of these changes and their influence on responses to RGC synaptic inputs have yet to be determined.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×