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Impact of CB1 Receptor Deletion on Visual Responses and Organization of Primary Visual Cortex in Adult Mice.
- Source :
-
Investigative ophthalmology & visual science [Invest Ophthalmol Vis Sci] 2015 Dec; Vol. 56 (13), pp. 7697-707. - Publication Year :
- 2015
-
Abstract
- Purpose: The endocannabinoids (eCBs) and their receptors are expressed in the cortex of developing animals where they act as a neuromodulating system during critical stages of brain development such as cell proliferation and migration, and axon guidance. Little is known on the impact of the cannabinoid system on cortical map formation and receptive field properties of cortical sensory neurons. The present study evaluates in vivo the functional organization of the primary visual cortex (V1) of mice lacking cannabinoid CB1R receptor (cnr1-/-).<br />Methods: Using optical imaging of intrinsic signals, azimuth, and elevation maps of cnr1-/- mice were compared with their wild-type littermates (cnr1+/+).<br />Results: Topographic maps were affected in mutant mice as they exhibited narrower visual field and changes in the shape of V1. CB1R exerted its action in an axis dependent manner as all changes were observed in the azimuth axis. Spatial frequency and contrast sensitivity were also compared between the two groups. Both properties were affected by the chronic lacking of CB1R as mutant mice exhibited a significantly lower contrast sensitivity as well as lower spatial frequency selectivity.<br />Conclusions: Taken together, these results suggest an important role for CB1R in cortical map formation. Our results also clearly demonstrate the impact of CB1R in the development of visual properties of primary visual cortex neurons. Because psychoactive effects of cannabis consumption on visual experience are mediated mainly through CB1R, our results could possibly explain neuronal mechanisms involved in those perceptual changes.
- Subjects :
- Animals
Cannabinoid Receptor Modulators metabolism
Cells, Cultured
Disease Models, Animal
Electroretinography
Endocannabinoids physiology
Fluorescent Antibody Technique, Indirect
Gene Deletion
Gene Expression Regulation
Mice
Mice, Inbred C57BL
Neurotransmitter Agents
Photic Stimulation
Receptor, Cannabinoid, CB1 genetics
Retina metabolism
Retinal Neurons metabolism
Vision Disorders metabolism
Vision Disorders pathology
Visual Cortex metabolism
Photoreceptor Cells, Vertebrate metabolism
Receptor, Cannabinoid, CB1 physiology
Retina pathology
Visual Cortex pathology
Subjects
Details
- Language :
- English
- ISSN :
- 1552-5783
- Volume :
- 56
- Issue :
- 13
- Database :
- MEDLINE
- Journal :
- Investigative ophthalmology & visual science
- Publication Type :
- Academic Journal
- Accession number :
- 26624499
- Full Text :
- https://doi.org/10.1167/iovs.15-17690