Effect of Brimonidine Tartrate on Ocular Hemodynamic Measurements

Lachkar, Yves; Migdal, Clive; Dhanjil, Surinda

doi:10.1001/archopht.116.12.1591

Cited by 51 publications

(23 citation statements)

References 19 publications

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“…Although several clinical studies document its safety and efficacy (20)(21)(22) more recent experimental and animal models suggest a neuroprotective effect of Brimonidine.…”

Section: Discussionmentioning

confidence: 99%

Brimonidine tartrate effect on retinal spreading depression depends on Müller cells

Oliveira¹,

Rodrigues²,

Alencar³

et al. 2014

Revista Brasileira De Oftalmologia

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Objective: Demonstrate the Brimonidine effect over Retinal Spreading Depression (SD). Brimonidine is an alpha-2-adrenergic receptor agonist, used in the management of glaucoma. Alpha2-agonists have been shown to be neuroprotective in various experimental models, however the molecular and cellular targets leading to these actions are still poorly defined. The SD of neuronal electric activity is a wave of cellular massive sustained depolarization that damages the nervous tissue. Local trauma, pressure, ischemic injuries and other chemical agents as high extracellular potassium concentration or glutamate, can trigger SD, leading to exaggerated focal electrical followed by an electrical silence. Methods: Using chicken retina as model, we performed alpha2-receptor detection by Western Blotting and Immunohistochemistry. After that we obtained electrical signals of SD by microelectrodes on retina in the absence or presence of Brimonidine. For in vivo visualization we observed retina with optical coherence tomography on normal state, with SD passing, and with SD + Brimonidine. Results: Our data demonstrated that: (1) alpha2-adrenergic receptors are present in Müller cells, (2) the treatment with Brimonidine decreases the SD's velocity as well as the voltage of SD waves and (3) OCT revealed that SD creates a hyper reflectance at inner plexiform layer, but on retinal treatment with brimonidine, SD was not visualized. Conclusion: Our study about brimonidine possible pathways of neuroprotection we observed it reduces SD (a neuronal damage wave), identified a new cellular target -the Müller cells, as well as, firstly demonstrated SD on OCT, showing that the inner plexiform layer is the main optically affected layer on SD.Keywords: Retina/drug effects; Adrenergic alpha-2 receptor agonists/therapeutic use; Glaucoma RESUMOObjetivo: Demonstrar o efeito do Tartarato de Brimonidina, um alfa2-agonista usado no manejo do glaucoma, sobre a depressão alastrante (DA) retiniana. Esses agonistas têm demonstrado ser neuroprotetores em vários modelos experimentais, contudo seus alvos celulares e moleculares continuam indefinidos. A DA da atividade elétrica neuronal é uma onda de despolarização celular massiva e sustentada que leva ao dano no tecido nervoso. Trauma local, pressão, isquemia e outros agentes químicos como o aumento do potássio extracelular e o glutamato podem disparar a DA, levando a uma atividade elétrica exagerada seguida de silêncio elétrico. Métodos: Usando a retina de pinto como modelo, realizamos a detecção do alfa2-receptor por Western Blotting e ensaio Imunohistoquímico. Após isso, obtivemos os sinais elétricos da DA através de microeletrodos inseridos na retina durante sua passagem na presença ou ausência de Brimonidina. Para visualização do tecido utilizamos o tomógrafo de coerência optica (OCT), analisando como é a retina no seu estado de repouso, durante a passagem da DA, e a DA + brimonidina. Resultados: Nossos dados demonstraram que: (1) os receptores alfa adrenérgicos presentes na retina são do subtipo-...

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“…Although several clinical studies document its safety and efficacy (20)(21)(22) more recent experimental and animal models suggest a neuroprotective effect of Brimonidine.…”

Section: Discussionmentioning

confidence: 99%

Brimonidine tartrate effect on retinal spreading depression depends on Müller cells

Oliveira¹,

Rodrigues²,

Alencar³

et al. 2014

Revista Brasileira De Oftalmologia

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“…In addition to the anterior segment of the eye, functional evidence exists for at least two of four known subtypes of α 2 -agonists [25]. Previous studies demonstrated that topical brimonidine and apraclonidine have no significant effect on the perfusion of the optic nerve, retina and choroid [26, 27]. There were no significant differences in the overall incidence of dry mouth, burning and stinging of the respective treatment groups.…”

Section: Discussionmentioning

confidence: 99%

A Comparison of the Short-Term Hypotensive Effects and Side Effects of Unilateral Brimonidine and Apraclonidine in Patients with Elevated Intraocular Pressure

Yüksel

Karabaş²,

Altıntaş³

et al. 2002

Ophthalmologica

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Purpose: To compare the short-term ocular hypotensive efficacy and side effects of 0.2% brimonidine and 0.5% apraclonidine in patients with elevated intraocular pressure (IOP). Methods: We performed a double-masked, placebo-controlled study to compare the efficacy of the application of 0.2% brimonidine and 0.5% apraclonidine for the effect of IOP, systemic blood pressure and heart rate in 20 newly diagnosed ocular hypertensive patients. Effects on the untreated fellow eye and ocular side effects were also determined. All measurements were performed 1, 2, 4, 6 and 8 h after the instillation of one drop. Results: Brimonidine and apraclonidine significantly reduced IOP from baseline at all observation times. No significant difference was observed between the treatment groups. IOP decreased significantly in the untreated fellow eye in the brimonidine group at 4-, 6- and 8-hour checks and at 6-hour checks in the apraclonidine group when compared with placebo. Blood pressure and heart rate decreased significantly in the brimonidine group compared with placebo. Apraclonidine did not affect blood pressure or heart rate any differently than placebo. The pupil diameter and the interpalpebral fissure width significantly increased in the apraclonidine group, but not in the brimonidine group. There were no significant differences in the overall incidence of foreign body sensation, burning and stinging and dry mouth in the treatment groups. Conclusions: In the short-term, brimonidine was effective in reducing IOP in patients with elevated IOP and was equivalent in efficacy to apraclonidine. On the other hand, a significant change in blood pressure and heart rate was observed with brimonidine; there was no change at all in the apraclonidine group.

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“…Lachkar et al, 1998 (10) , não observaram alterações na circulação retrobulbar com Doppler colorido após uso de tartarato de Brimonidina a 0,2% em pacientes com hipertensão ocular. Explicam estes resultados pela alta especificidade da Brimonidina pelos receptores adrenérgicos alfa-2.…”

Section: Discussionunclassified

Efeito da brimonidina na circulação retrobulbar em pacientes com glaucoma: estudo com Doppler colorido

Silva

Rollo

Schellini

2001

Arq. Bras. Oftalmol.

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Efeito da brimonidina na circulação retrobulbar em pacientes com glaucoma -estudo com Doppler colorido Objetivo: Avaliar o efeito do tartarato de brimonidina a 0,2% tópico, instilado de 12/12 horas, na circulação retrobulbar em pacientes portadores de glaucoma. Métodos: Foram estudados os 2 olhos de 16 pacientes portadores de glaucoma primário de ângulo aberto e glaucoma crônico de ângulo estreito com iridotomia. Usando o Doppler colorido foram avaliados: velocidade sistólica máxima, velocidade diastólica final e índice de resistência das artéria central da retina, artéria ciliar posterior curta temporal e artéria oftálmica. As avaliações foram feitas antes e depois do uso da brimonidina. Resultados: O tartarato de brimonidina a 0,2% aumentou significativamente a velocidade sistólica máxima (28,24 para 34,23 cm/seg) e velocidade diastólica final (6,62 para 8,10 cm/seg) no olho direito e reduziu o índice de resistência (0,75 para 0,71) no olho esquerdo da artéria oftálmica. Conclusão: O tartarato de brimonidina 0,2% 2x/dia aumentou significativamente a velocidade sistólica máxima e velocidade diastólica final e reduziu índice de resistência da artéria oftálmica de pacientes glaucomatosos. Este efeito sugere que a brimonidina pode beneficiar pacientes glaucomatosos com insuficiência vascular na cabeça do nervo óptico. Effect of brimonidine on the retrobulbar circulation in glaucomatous patientsa color Doppler study

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Effect of Brimonidine Tartrate on Ocular Hemodynamic Measurements

Cited by 51 publications

References 19 publications

Brimonidine tartrate effect on retinal spreading depression depends on Müller cells

Brimonidine tartrate effect on retinal spreading depression depends on Müller cells

A Comparison of the Short-Term Hypotensive Effects and Side Effects of Unilateral Brimonidine and Apraclonidine in Patients with Elevated Intraocular Pressure

Efeito da brimonidina na circulação retrobulbar em pacientes com glaucoma: estudo com Doppler colorido

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