Search results for "ocular"
showing 10 items of 1219 documents
Subsynaptic Distribution, Lipid Raft Targeting and G Protein-Dependent Signalling of the Type 1 Cannabinoid Receptor in Synaptosomes from the Mouse H…
2021
Numerous studies have investigated the roles of the type 1 cannabinoid receptor (CB1) in glutamatergic and GABAergic neurons. Here, we used the cell-type-specific CB1 rescue model in mice to gain insight into the organizational principles of plasma membrane targeting and Gαi/o protein signalling of the CB1 receptor at excitatory and inhibitory terminals of the frontal cortex and hippocampus. By applying biochemical fractionation techniques and Western blot analyses to synaptosomal membranes, we explored the subsynaptic distribution (pre-, post-, and extra-synaptic) and CB1 receptor compartmentalization into lipid and non-lipid raft plasma membrane microdomains and the signalling properties.…
Neuron-type specific cannabinoid-mediated G protein signalling in mouse hippocampus
2013
Type 1 cannabinoid receptor (CB1) is expressed in different neuronal populations in the mammalian brain. In particular, CB1 on GABAergic or glutamatergic neurons exerts different functions and display different pharmacological properties in vivo. This suggests the existence of neuron-type specific signalling pathways activated by different subpopulations of CB1. In this study, we analysed CB1 expression, binding and signalling in the hippocampus of conditional mutant mice, bearing CB1 deletion in GABAergic (GABA-CB1-KO mice) or cortical glutamatergic neurons (Glu-CB1-KO mice). Compared to their wild-type littermates, Glu-CB1-KO displayed a small decrease of CB1 mRNA amount, immunoreactivity…
Co-expression of the voltage-gated potassium channel Kv1.4 with transient receptor potential channels (TRPV1 and TRPV2) and the cannabinoid receptor …
2006
Potassium channels contribute to basic neuronal excitability and modulation. Here, we examined expression patterns of the voltage-gated potassium channel Kv1.4, the nociceptive transduction channels TRPV1 and TRPV2 as well as the putative anti-nociceptive cannabinoid receptor CB1 by immunofluorescence double-labelings in sections of rat dorsal root ganglia (DRGs). Kv1.4, TRPV1 and CB1 were each detected in about one third of neurons (35.7+/-0.5%, 29.4+/-1.1% and 36.4+/-0.5%, respectively, mean diameter 19.1+/-0.3 microm). TRPV2 was present in 4.4+/-0.4% of all neurons that were significantly larger in diameter (27.4+/-0.7 microm; P < 0.001). Antibody double-labeling revealed that the majori…
Cell type‐specific genetic reconstitution of CB1 receptor subsets to assess their role in exploratory behaviour, sociability, and memory
2021
Several studies support the notion that exploratory behaviour depends on the functionality of the cannabinoid type 1 (CB1) receptor in a cell type-specific manner. Mice lacking the CB1 receptor in forebrain GABAergic or dorsal telencephalic glutamatergic neurons have served as essential tools revealing the necessary CB1 receptor functions in these two neuronal populations. However, whether these specific CB1 receptor populations are also sufficient within the endocannabinoid system for wild-type-like exploratory behaviour has remained unknown. To evaluate cell-type-specific sufficiency of CB1 receptor signalling exclusively in dorsal telencephalic glutamatergic neurons (Glu-CB1-RS) or in fo…
Postnatal development of cannabinoid receptor type 1 expression in rodent somatosensory cortex
2007
Endocannabinoids are powerful modulators of synaptic transmission that act on presynaptic cannabinoid receptors. Cannabinoid receptor type 1 (CB1) is the dominant receptor in the CNS, and is present in many brain regions, including sensory cortex. To investigate the potential role of CB1 receptors in cortical development, we examined the developmental expression of CB1 in rodent primary somatosensory (barrel) cortex, using immunohistochemistry with a CB1-specific antibody. We found that before postnatal day (P) 6, CB1 receptor staining was present exclusively in the cortical white matter, and that CB1 staining appeared in the gray matter between P6 and P20 in a specific laminar pattern. CB1…
Implantation of the modified endocapsular bending ring in pediatric cataract surgery using a viscoadaptive viscoelastic agent.
1999
Cataract surgery and intraocular lens (IOL) implantation in pediatric eyes remain controversial. Using a viscoadaptive viscoelastic agent, we implanted a modified capsular bending ring (CBR) as well as an acrylic IOL with a sharp-optic-edge design in the capsular bag. All operated eyes demonstrated a low postoperative inflammatory reaction and a clinically well-centered IOL. The band-shaped, sharp-edged CBR facilitates the creation of a sharp, discontinuous bend in the equatorial capsule, which prevents anterior and posterior capsule opacification. Combining the viscoadaptive viscoelastic agent and the CBR enhances the safety of primary and secondary posterior chamber IOL implantation in pe…
Ocular Comorbidities and the Relationship between Eye Diseases and Systemic Disorders
2016
Patients with ocular disorders may have additional ophthalmic problems that can have an impact on both morbidity and vision. Ocular comorbidities are commonly associated with vision-related disability and decreased quality of life related to visual impairment. The majority of studies on this topic deal with cataracts, glaucoma, uveitis, and/or retinopathies. It is important to summarize the available evidence to date on the association of one or several ocular diseases and the implications these comorbidities have on prognosis and therapy. The relationship between eye disorders and systemic diseases has recently drawn special interest. The increasing prevalence of neurodegenerative disorder…
Coping with continual danger: assessing alertness to visual disturbances in crucian carp following long-term exposure to chemical alarm signals.
2013
Chemical alarm signals in fish are passively released into the water from ruptured epidermal cells, and induce instant fright responses in conspecifics. Fish also display alarm responses to injured heterospecific skin, as well as to scent of piscivorous predators that have ingested prey. A conspicuous alertness to visual disturbances has also been observed in fish following long-term exposure to extracts of filtered, homogenized skin, but the chemical inducers of such vigilance are actually unknown. We tested if a continual exposure to water-soluble alarm signals, from either conspecifics or heterospecifics, affects alertness of fish. Based on previous experience, it was assumed that alertn…
Central nicotinic receptors, neurotrophic factors and neuroprotection
2000
The multiple combinations of nAChR subunits identified in central nervous structures possess distinct pharmacological and physiological properties. A growing number of data have shown that compounds interacting with neuronal nAChRs have, both in vivo and in vitro, the potential to be neuroprotective and that treatment with nAChR agonists elicit long-lasting improving of cognitive performance in a variety of behavioural tests in rats, monkeys and humans. Epidemiological and clinical studies suggested also a potential neuroprotective/trophic role of (-)-nicotine in neurodegenerative disease, such as Alzheimer's and Parkinson's disease. Taken together experimental and clinical data largely ind…
The translocation of signaling molecules in dark adapting mammalian rod photoreceptor cells is dependent on the cytoskeleton.
2008
In vertebrate rod photoreceptor cells, arrestin and the visual G-protein transducin move between the inner segment and outer segment in response to changes in light. This stimulus dependent translocation of signalling molecules is assumed to participate in long term light adaptation of photoreceptors. So far the cellular basis for the transport mechanisms underlying these intracellular movements remains largely elusive. Here we investigated the dependency of these movements on actin filaments and the microtubule cytoskeleton of photoreceptor cells. Co-cultures of mouse retina and retinal pigment epithelium were incubated with drugs stabilizing and destabilizing the cytoskeleton. The actin a…