Category Archives: Glaucoma

Neuroprotective effects of cannabidiol in endotoxin-induced uveitis: critical role of p38 MAPK activation.

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“Degenerative retinal diseases are characterized by inflammation and microglial activation.

The nonpsychoactive cannabinoid, cannabidiol (CBD), is an anti-inflammatory in models of diabetes and glaucoma.

We tested the hypothesis that retinal inflammation and microglia activation are initiated and sustained by oxidative stress and p38 mitogen-activated protein kinase (MAPK) activation, and that CBD reduces inflammation by blocking these processes…

Retinal inflammation and degeneration in uveitis are caused by oxidative stress.

CBD exerts anti-inflammatory and neuroprotective effects by a mechanism that involves blocking oxidative stress and activation of p38 MAPK and microglia.”

http://www.ncbi.nlm.nih.gov/pubmed/19052649

[The role of endocannabinoid system in physiological and pathological processes in the eye].

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“Plant of Cannabis sativa/ marihuana except for its psychotropic effects possesses a range of pharmacological properties, that has been utilized for medical purposes over a period of millenia.

Investigations concerning biochemical mechanism of action of the main and most active pharmacological compound of Cannabis sativa, cannabinoid 9-THC, contributed to the discovery of cannabinoid receptors both in the central nervous system (CNS) and peripheral tissues, that mediated actions of this substance.

The discovery made possible identification of a new, endogenous signaling system referred to as the endocannabinoid system.

Besides cannabinoid receptors CB1 and CB2, the system includes it’s endogenic ligands (endocannabinoids) and compounds that participate in their biosynthesis and inactivation. Structure and functioning of the endocannabinoid system is conservative in all vertebrates.

It’s activation with plant, synthetic and endogenous cannabinoids has an influence on multiple physiological and pathological processes within the eye.”

http://www.ncbi.nlm.nih.gov/pubmed/19195174

Neuroprotective Effect of(−)Δ9-Tetrahydrocannabinol and Cannabidiol in N-Methyl-d-Aspartate-Induced Retinal Neurotoxicity

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“In glaucoma, the increased release of glutamate is the major cause of retinal ganglion cell death. Cannabinoids have been demonstrated to protect neuron cultures from glutamate-induced death.

In this study, we test the hypothesis that glutamate causes apoptosis of retinal neurons via the excessive formation of peroxynitrite, and that the neuroprotective effect of the psychotropic Δ9-tetrahydroxycannabinol (THC) or nonpsychotropic cannabidiol (CBD) is via the attenuation of this formation…

The neuroprotection by THC and CBD was because of attenuation of peroxynitrite.

The effect of THC was in part mediated by the cannabinoid receptor CB1.

These results suggest the potential use of CBD as a novel topical therapy for the treatment of glaucoma.

THC and CBD, are similarly potent antioxidants that protect neuron cultures from glutamate-induced cell death or oxidative stress…

In addition to possessing neuroprotective or retinal neuroprotective activity… cannabinoids, such as THC, have been demonstrated to induce dose-related reductions in intraocular pressure in human and in animal models. 

This suggests that cannabinoids may offer a multifaceted therapy for glaucoma.

In conclusion, our results indicate that lipid peroxidation and ONOO− formation play an important role in NMDA-induced retinal neurotoxicity and cell loss in the retina, and that THC and CBD, by reducing the formation of these compounds, are effective neuroprotectants.

The present studies could form the basis for the development of new topical therapies for the treatment of glaucoma.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1892413/

http://www.thctotalhealthcare.com/category/glaucoma-2/

Intraocular pressure, ocular toxicity and neurotoxicity after administration of cannabinol or cannabigerol.

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“Cannabinol or cannabigerol was administered to cats topically in doses of 250, 500 and 1000 micrograms as a single drop or chronically via osmotic minipumps (20 micrograms hr-1) over a period of 9 days. While cannabinol had a modest effect on intraocular pressure after a single dose, it caused a more significant reduction in ocular tension during chronic administration. Cannabigerol had similar effects, but the magnitude of response to its chronic administration was greater. Cannabinol but not cannabigerol caused conjunctival erythema and hyperemia. After systemic administration of cannabinol (20, 40 or 80 mg kg-1) to rats, 8-13 Hz polyspike discharges appeared in the electrocorticogram during wakefulness and during rapid eye movement sleep episodes. Cannabigerol (10, 30 and 100 mg kg-1) lacked this effect.

These results indicate that chronic administration of these cannabinoids lowers ocular tension considerably.

Like marihuana and delta-9-tetrahydrocannabinol, cannabinol produced both ocular toxicity and neurotoxicity. As cannabigerol lacked these toxicities, it appears that the ocular hypotensive effect of this cannabinoid is somewhat dissociable from both the adverse central and ocular effects accompanying marihuana intake.”

http://www.ncbi.nlm.nih.gov/pubmed/6499952

A comparison of the ocular and central effects of delta 9-tetrahydrocannabinol and cannabigerol.

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“Both delta 9-tetrahydrocannabinol (delta 9-THC) and cannabigerol, two naturally occurring marihuana cannabinoids, produced only a modest fall in intraocular pressure after acute topical application to the eyes of cats.

After chronic administration unilaterally to the cornea via Alzet osmotic minipumps and connecting extraocular cannulas, however, a considerable fall in ocular tension amounting to 4 to 7 mm Hg occurred. After systemic administration of delta 9-THC to rats, polyspike discharges appeared in the cortical electroencephalogram initially during wakefulness and behavioral depression. These polyspikes subsequently became evident within rapid eye movement sleep episodes. Cannabigerol was devoid of this effect. After removal of either sympathetic or parasympathetic input to the eyes of cats, the intraocular pressure lowering effect of delta 9-THC was not changed. Neither delta 9-THC nor cannabigerol altered the rate of formation of aqueous humor. On the other hand, both cannabinoids produced a two-to three-fold increase in aqueous outflow facility.

These results suggest that cannabigerol and related cannabinoids may have therapeutic potential for the treatment of glaucoma.”

http://www.ncbi.nlm.nih.gov/pubmed/1965836

Cannabinoids: a novel treatment for glaucoma

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Acta Ophthalmologica

“…cannabinoids are emerging novel agents for the treatment of glaucoma.

Although increased intraocular pressure (IOP) is a risk factor, associated retinal damage is of prime concern. This study determines the ability of cannabinoids to decrease IOP and confer neuroprotection…

Conclusion: Topically applied cannabinoids are effective agents that reduce IOP and confer neuroprotection and are prime candidates for potential glaucoma treatment.”

http://onlinelibrary.wiley.com/doi/10.1111/j.1755-3768.2014.T022.x/abstract

http://www.thctotalhealthcare.com/category/glaucoma-2/

Neuroprotective effects of the cannabinoid agonist HU210 on retinal degeneration.

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“Cannabinoids have been demonstrated to exert neuroprotective effects on different types of neuronal insults.

Here we have addressed the therapeutic potential of the synthetic cannabinoid HU210 on photoreceptor degeneration, synaptic connectivity and functional activity of the retina in the transgenic P23H rat, an animal model for autosomal dominant retinitis pigmentosa (RP)…

These data suggest that cannabinoids are potentially useful to delay retinal degeneration in RP patients.”

http://www.ncbi.nlm.nih.gov/pubmed/24495949

Therapeutic potential of cannabinoid medicines.

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Drug Testing and Analysis

“Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines.

The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology.

In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/24006213

http://onlinelibrary.wiley.com/doi/10.1002/dta.1529/abstract

Doctor: Marijuana is a needed option

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Dr. Blick sits in the pharmacy at the Circle Care Center in Norwalk, Conn. Along with synthetic medications, Dr. Blick looks forward to utilizing the benefits of medical marijuana for patients with a variety of medical conditions including cancer, glaucoma and HIV/AIDS. Photo: Autumn Driscoll / Connecticut Post

“There was a personal reason why Dr. Gary Blick became one of the nearly 100 physicians in the state who are licensed to prescribe medical marijuana.”I did this because my 91-year-old mother, who has glaucoma,” he said. “Her glaucoma eye drops had failed to produce the desired results and she was facing surgery.”

Glaucoma is a disease in which the eye typically has excessive internal pressure, damaging the nerve fibers of the retina, the delicate tissue at the back of the eye that’s sensitive to light and color.

“She was needing surgery to repair her eyes,” he said. “But after we started her on medical marijuana, her pressures dropped, and when she stopped smoking marijuana, the pressures went back up again.”

He said her testimony in Hartford last year had the legislative committee considering the bill “in stitches,” even though her testimony countered testimony of the president of the Connecticut Society of Eye Physicians, who said marijuana would not be helpful to glaucoma patients.

“So one of the senators said, `Are you aware of Gloria Blick‘s testimony?’ To which he replied, `Well, I guess it would help some people.’ To which the senator replied, `Isn’t that what we’re here for?’ ”

Blick sees medical marijuana as just one of the arsenal of options that physicians should have to ease pain and provide relief for various diseases.”

More: http://www.ctpost.com/local/article/Doctor-Marijuana-is-a-needed-option-4740995.php#src=fb

Cannabinoid Receptor CB2 Modulates Axon Guidance.

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“Navigation of retinal projections towards their targets is regulated by guidance molecules and growth cone transduction mechanisms. Here, we present in vitro and in vivo evidences that the cannabinoid receptor 2 (CB2R) is expressed along the retino-thalamic pathway and exerts a modulatory action on axon guidance….

Overall, this study demonstrates that the contribution of endocannabinoids to brain development is not solely mediated by CB1R, but also involves CB2R.”

http://www.ncbi.nlm.nih.gov/pubmed/23951024