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Cui YK, Pan L, Lam T, Wen CY, Do CW. Mechanistic links between systemic hypertension and open angle glaucoma. Clin Exp Optom 2021; 105:362-371. [PMID: 34402761 DOI: 10.1080/08164622.2021.1964332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Systemic hypertension or hypertension is a very common chronic age-related disease worldwide. It is typically characterised by a sustained elevation of blood pressure, particularly when the systolic blood pressure and/or diastolic blood pressure are of more than 140 mmHg and 90 mmHg, respectively. If hypertension is not well controlled, it may lead to an increased risk of stroke and heart attack. It has been shown that hypertension is linked to various ocular diseases, including cataract, diabetic retinopathy, age-related macular degeneration, and glaucoma. Glaucoma is the leading cause of irreversible blindness worldwide. Primary open angle glaucoma is the most common form of the disease and is usually characterised by an increase in intraocular pressure. This condition, together with normal tension glaucoma, constitutes open angle glaucoma. Systemic hypertension has been identified as a risk factor for open angle glaucoma. It is speculated that blood pressure is involved in the pathogenesis of open angle glaucoma by altering intraocular pressure or ocular blood flow, or both. Recent evidence has shown that both extremely high and low blood pressure are associated with increased risk of open angle glaucoma. Additional pathogenic mechanisms, including increased inflammation likely to be involved in the development and progression of these two diseases, are discussed.
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Affiliation(s)
- Ying-Kun Cui
- School of Optometry, The Hong Kong Polytechnic University, Shenzhen, Hong Kong SAR
| | - Li Pan
- School of Optometry, The Hong Kong Polytechnic University, Shenzhen, Hong Kong SAR
| | - Tim Lam
- School of Optometry, The Hong Kong Polytechnic University, Shenzhen, Hong Kong SAR
| | - Chun-Yi Wen
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Shenzhen, Hong Kong SAR
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Shenzhen, Hong Kong SAR.,Centre For Eye and Vision Research, Shenzhen, Hong Kong SAR
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Antończyk A, Kubiak-Nowak D, Borawski W, Kiełbowicz Z, Danielewska ME. The effect of changes in cardiovascular activity on corneal biomechanics and pulsation in rabbits. Sci Rep 2020; 10:22249. [PMID: 33335224 PMCID: PMC7747746 DOI: 10.1038/s41598-020-79219-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 12/04/2020] [Indexed: 11/24/2022] Open
Abstract
The aim was to assess the relationships between cardiovascular activity, corneal pulse characteristics, and corneal biomechanics in rabbits. Seventeen rabbits were randomly assigned to one of two anesthetic regimens to induce differences in arterial blood pressure and heart rate. Experimental protocol included measuring blood flow parameters in the ophthalmic artery by color Doppler imaging, corneal biomechanical parameters using a non-contact tonometer Corvis ST, and the corneal pulse (CP) signal using a non-contact ultrasonic technique. Statistically significantly lower mean values of normalized amplitudes of higher CP harmonics and changes in eight of the twelve corneal biomechanical parameters were observed in the rabbit group with lower arterial blood pressure and higher heart rate, intraocular pressure, and resistive index. The results of partial correlations showed that the CP signal energy and amplitude of its first harmonic correlate with the resistive index, diastolic and mean arterial pressures, whereas no statistically significant correlation was found between any of the CP parameters and intraocular pressure. Our pilot study indicates, for the first time, that non-contact and continuous measuring of corneal pulse allows indirectly assessing changes in cardiovascular activity when the confounding effect of intraocular pressure is eliminated.
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Affiliation(s)
- Agnieszka Antończyk
- Department of Surgery, Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences, pl. Grunwaldzki 51, 50-366, Wrocław, Poland.
| | - Dominika Kubiak-Nowak
- Department of Surgery, Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences, pl. Grunwaldzki 51, 50-366, Wrocław, Poland
| | - Wojciech Borawski
- Department of Surgery, Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences, pl. Grunwaldzki 51, 50-366, Wrocław, Poland
| | - Zdzisław Kiełbowicz
- Department of Surgery, Faculty of Veterinary Medicine, Wroclaw University of Environmental and Life Sciences, pl. Grunwaldzki 51, 50-366, Wrocław, Poland
| | - Monika E Danielewska
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370, Wrocław, Poland
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Systemic Hypertension Effects on the Ciliary Body and Iris. An Immunofluorescence Study with Aquaporin 1, Aquaporin 4, and Na⁺, K⁺ ATPase in Hypertensive Rats. Cells 2018; 7:cells7110210. [PMID: 30428541 PMCID: PMC6262422 DOI: 10.3390/cells7110210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 11/16/2022] Open
Abstract
Aquaporin 1 (AQP1) and aquaporin 4 (AQP4) have been identified in the eye as playing an essential role in the formation of the aqueous humor along with the Na+/K+ ATPase pump. Different authors have described the relationship between blood pressure, aqueous humor production, and intraocular pressure with different conclusions, with some authors supporting a positive correlation between blood pressure and intraocular pressure while others disagree. The aim of this work was to study the effect of high blood pressure on the proteins involved in the production of aqueous humor in the ciliary body (CB) and iris. For this purpose, we used the eyes of spontaneously hypertensive rats (SHR) and their control Wistar-Kyoto rats (WKY). Immunofluorescence was performed in different eye structures to analyze the effects of hypertension in the expression of AQP1, AQP4, and the Na+/K+ ATPase α1 and α2 subunits. The results showed an increase in AQP1 and Na+/K+ ATPase α1 and a decrease in AQP4 and Na+/K+ ATPase α2 in the CB of SHR, while an increase in AQP4 and no significant differences in AQP1 were found in the iris. Therefore, systemic hypertension produced changes in the proteins implicated in the movement of water in the CB and iris that could influence the production rate of aqueous humor, which would be affected depending on the duration of systemic hypertension.
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Skrzypecki J, Grabska-Liberek I, Przybek J, Ufnal M. A common humoral background of intraocular and arterial blood pressure dysregulation. Curr Med Res Opin 2018; 34:521-529. [PMID: 29219620 DOI: 10.1080/03007995.2017.1415203] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND It has been postulated that intraocular pressure, an important glaucoma risk factor, correlates positively with arterial blood pressure (blood pressure). However, results of experimental and clinical studies are often contradictory. It is hypothesized that, in some hypertensive patients, disturbances in intraocular pressure regulation may depend on biological effects of blood borne hormones underlying a particular type of hypertension, rather than on blood pressure level itself. REVIEW This review compares the effects of hormones on blood pressure and intraocular pressure, in order to identify a hormonal profile of hypertensive patients with an increased risk of intraocular pressure surge. The PUBMED database was searched to identify pre-clinical and clinical studies investigating the role of angiotensin II, vasopressin, adrenaline, noradrenaline, prostaglandins, and gaseous transmitters in the regulation of blood pressure and intraocular pressure. RESULTS Studies included in the review suggest that intraocular and blood pressures often follow a different pattern of response to the same hormone. For example, vasopressin increases blood pressure, but decreases intraocular pressure. In contrast, high level of nitric oxide decreases blood pressure, but increases intraocular pressure. CONCLUSIONS Arterial hypertension is associated with altered levels of blood borne hormones. Contradicting results of studies on the relationship between arterial hypertension and intraocular pressure might be partially explained by diverse effects of hormones on arterial and intraocular pressures. Further studies are needed to evaluate if hormonal profiling may help to identify glaucoma-prone patients.
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Affiliation(s)
- Janusz Skrzypecki
- a Department of Experimental Physiology and Pathophysiology, Laboratory of Centre for Preclinical Research , Medical University of Warsaw , Warsaw , Poland
- b Department of Ophthalmology , Medical Center for Postgraduate Education , Warsaw , Poland
| | - Iwona Grabska-Liberek
- b Department of Ophthalmology , Medical Center for Postgraduate Education , Warsaw , Poland
| | - Joanna Przybek
- c Department of Experimental and Clinical Pharmacology , Medical University of Warsaw , Poland
| | - Marcin Ufnal
- a Department of Experimental Physiology and Pathophysiology, Laboratory of Centre for Preclinical Research , Medical University of Warsaw , Warsaw , Poland
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Skrzypecki J, Ufnal M. The Upright Body Position Increases Translaminar Pressure Gradient in Normotensive and Hypertensive Rats. Curr Eye Res 2017; 42:1634-1637. [DOI: 10.1080/02713683.2017.1349155] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Janusz Skrzypecki
- Department of Experimental Physiology and Pathophysiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
- Department of Ophthalmology, Centre of Postgraduate Medical Education, Warsaw, Poland
| | - Marcin Ufnal
- Department of Experimental Physiology and Pathophysiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
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Wang RF, Podos SM, Serle JB, Baltatu OC. Effect of SPP 635, a renin inhibitor, on intraocular pressure in glaucomatous monkey eyes. Exp Eye Res 2011; 94:146-9. [PMID: 22173206 DOI: 10.1016/j.exer.2011.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/22/2011] [Accepted: 11/26/2011] [Indexed: 11/17/2022]
Abstract
The effect of topical application of SPP 635, a renin inhibitor, on intraocular pressure (IOP) was evaluated in the eyes of monkeys with laser induced unilateral glaucoma. A multiple-dose study was performed in 8 glaucomatous monkey eyes with 3 concentrations of SPP 635, 0.2%, 0.3% and 0.4%. IOP was measured hourly for 6 h on each day of the study beginning at 9:30 a.m. Following one baseline day (untreated) and one vehicle-treated day (50 μl drop of vehicle to the glaucomatous eye at 9:30 a.m.), a 50 μl drop (25 μl × 2) of SPP 635, 0.2%, 0.3% or 0.4%, was topically applied to the glaucomatous eye at 9:30 a.m. and 3:30 p.m. for 5 consecutive days. Twice daily administration of each of the 3 concentrations of SPP 635 for 5 days significantly (p < 0.05) reduced IOP. The maximum reduction in IOP occurred 3 or 4 h after morning dosing and was 4.3 ± 0.8 (mean ± SEM) mmHg (14%) for 0.2% SPP 635, 5.3 ± 1.0 mmHg, (19%) for 0.3% SPP 635, and 8.0 ± 1.3 mmHg (25%) for 0.4% SPP 635. The longest duration of IOP reduction was for 6 h with 0.2% or 0.3% SPP 635, and was for at least 18 h with 0.4% concentration. Compared to 0.2% or 0.3% concentrations, 0.4% SPP 635 produced a greater (p < 0.05) and longer duration of IOP reduction (18 vs. 6 h). Mild conjunctival discharge appeared in 2 of 8 eyes, and hyperemia appeared in 2 eyes with the 0.3% and 0.4% concentrations on treatment days 3 and 5. Topically applied SPP 635, a new renin inhibitor, reduces IOP in glaucomatous monkeys in a dose-dependent manner. Renin inhibitors, are a novel class of compounds which may have potential for the treatment of glaucoma.
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Affiliation(s)
- Rong-Fang Wang
- Department of Ophthalmology, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1183, New York, NY 10029, United States.
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Cuny CS, Joachim SC, Gramlich OW, Gottschling PF, Pfeiffer N, Grus FH. Repeated intraocular pressure measurement in awake Lewis rats does not bias retinal ganglion cell survival. Curr Eye Res 2011; 35:1034-9. [PMID: 20958192 DOI: 10.3109/02713683.2010.498654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The TonoPen applanation tonometry is an established method for intraocular pressure (IOP) measurement. The IOP is one of the main variables affecting retinal ganglion cell (RGC) loss in experimental animal models in ophthalmology and the main risk factor for human glaucoma. In this study, we examined if IOP measurements with the TonoPen itself lead to retinal ganglion cell loss or any other possible retina damages, such as intraocular bleedings or ablation, in Lewis rats. METHODS Three groups of rats (n = 5 each) were formed. IOP monitoring, using a TonoPen XL, was performed on groups 1 and 3. Animals in groups 1 and 2 received funduscopies before and after one and two weeks of the study, in order to detect possible abnormalities. After two weeks, retinal flatmounts were stained to detect ganglion cells. RGCs were manually counted in eight predefined areas to compare mean RGC densities between groups 1 and 2 (IOP readings vs. no readings), using student t-test. RESULTS No significant difference in RGC density between animals that underwent IOP readings and controls could be observed (p = 0.8). As expected, no IOP alterations were monitored in groups 1 and 3 throughout the study. No retinal abnormalities, such as bleeding or retina ablation, were detectable. CONCLUSION We could detect no effects on retinal ganglion cell survival in Lewis rats or any other damages to the retina caused by IOP measurements using a TonoPen XL. This study proposes that repeated applanation tonometry does not affect RGC numbers, one of the main monitored variables in most glaucoma model studies. Therefore, the use of a TonoPen XL for repeated IOP monitoring in Lewis rats can be considered harmless.
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Affiliation(s)
- C S Cuny
- Experimental Ophthalmology, Department of Ophthalmology, University Medical Center, Johannes Gutenberg University, Mainz, Germany
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Palm DE, Shue SG, Keil LC, Balaban CD, Severs WB. Effects of angiotensin, vasopressin and atrial natriuretic peptide on intraocular pressure in anesthetized rats. Neuropeptides 1995; 29:193-203. [PMID: 8584137 DOI: 10.1016/0143-4179(95)90061-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of atrial natriuretic peptide (ANP), vasopressin (AVP) and angiotensin (ANG) on blood and intraocular pressures of pentobarbital anesthetized rats were evaluated following intravenous, intracerebroventricular or anterior chamber routes of administration. Central injections did not affect intraocular pressure. Equipressor intravenous infusions of ANG raised, whereas AVP decreased, intraocular pressure. Direct infusions of a balanced salt solution (0.175 microliter/min) raised intraocular pressure between 30 and 60 min. Adding ANG or ANP slightly reduced this solvent effect but AVP was markedly inhibitory. An AVP-V1 receptor antagonist reversed the blunting of the solvent-induced rise by the peptide, indicating receptor specificity. Acetazolamide pretreatment lowered intraocular pressure, but the solvent-induced rise in intraocular pressure and inhibition by AVP still occurred without altering the temporal pattern. Thus, these effects appear unrelated to aqueous humor synthesis rate. The data support the possibility of intraocular pressure regulation by peptides acting from the blood and aqueous humor.
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Affiliation(s)
- D E Palm
- Department of Pharmacology, College of Medicine, Pennsylvania State University, Hershey 17033, USA
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Ricci B, Minicucci G, Manfredi A, Santo A. Oxygen-induced retinopathy in the newborn rat: effects of hyperbarism and topical administration of timolol maleate. Graefes Arch Clin Exp Ophthalmol 1995; 233:226-30. [PMID: 7797087 DOI: 10.1007/bf00183596] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Lesions resembling those of human retinopathy of prematurity can be provoked in newborn Wistar rats by exposure to an FiO2 of 80% for the first 5 days of life followed by 5 days recovery under room-air conditions. METHODS We evaluated the effects of moderate hyperbarism (+60.75 kPa, i.e. 455 mmHg or 0.6 atm) and topical administration of 0.25% timolol maleate on oxygen-induced retinopathy (OIR) in this experimental model. RESULTS OIR (including neovascularization in most cases) was observed in 100% of the retinas of normobaric oxygen-reared ratlings that did not receive timolol. OIR was less frequent in oxygen-reared ratlings treated with hyperbarism (60%) or timolol (65%). Hyperbaric oxygen supplementation combined with timolol treatment during both the hyperoxic and room-air phases reduced the incidence of OIR to 30%. There was no sign of vasoproliferation in any of the retinas from the latter three groups. CONCLUSIONS The highly significant protective effects of hyperbarism and timolol observed in this study are not fully understood. We speculate that vasoconstriction induced by the hyperbarism reduces the amount of oxygen that reaches the retina from the choroid during O2 supplementation, while an increased ocular perfusion pressure caused by timolol-induced reduction of the intraocular pressure might decrease the stimulus to vasoproliferation that normally occurs with room-air recovery.
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Affiliation(s)
- B Ricci
- Department of Ophthalmology, Catholic University of the Sacred Heart, Faculty of Medicine and Surgery, Rome, Italy
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Ricci B, Calogero G, Caprilli A, Quaranta-Leoni FM. Reduced severity of oxygen-induced retinopathy in the newborn rat after topical administration of timolol maleate. A preliminary study. Doc Ophthalmol 1991; 77:47-56. [PMID: 1752190 DOI: 10.1007/bf00154877] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of timolol maleate on intraocular pressure (IOP) and the severity of retinopathy induced by exposure to 80% oxygen were studied in newborn Wistar rats. One drop of timolol maleate (0.25%) instilled in each eye twice a day for the first ten days of life substantially reduced intraocular pressure without significantly modifying arterial pressure. Forty percent of the ratlings treated in this way failed to develop oxygen-induced retinopathy (OIR) after exposure to 80% oxygen for the first five days of life; in the other 60% OIR was less severe than that seen in an identically oxygenated group that did not receive timolol. The authors hypothesize that the pharmacologically induced reduction in IOP may have attenuated the effects of the high concentrations of oxygen on the immature retinal vessels by improving the ocular perfusion pressure. The possibility that timolol maleate also exerts a direct action on the caliber of these vessels cannot be excluded.
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Affiliation(s)
- B Ricci
- Department of Ophthalmology, Catholic University, Rome, Italy
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Jumblatt JE, Hackmiller RC. Potentiation of norepinephrine secretion by angiotensin II in the isolate rabbit iris-ciliary body. Curr Eye Res 1990; 9:169-76. [PMID: 1692269 DOI: 10.3109/02713689008995203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The prejunctional effects of angiotensin II (AII) on stimulation-evoked secretion of 3H-norepinephrine (3H-NE) were investigated by in vitro methods in isolated, superfused rabbit iris-ciliary body preparations. AII (0.1-10 nM) concentration-dependently enhanced the field- stimulated release of 3H-NE (EC50 = 0.1 nM), nearly doubling evoked neurotransmitter release with no apparent effect on spontaneous 3H-NE efflux. The response to 1 nM AII was abolished by the selective AII receptor antagonist saralasin [( Sar1,Val5, Ala8]-angiotensin II; 500 nM), which alone did not modify 3H-NE overflow. AII-mediated effects on neurosecretion were partially additive to those of forskolin and were not potentiated by phosphodiesterase inhibition, suggesting that AII utilizes a mechanism other than increased cAMP synthesis to facilitate neurotransmitter release. AII also strongly enhanced calcium ionophore (A23187)-induced 3H-NE release in iris-ciliary body segments, indicating that AII can modulate calcium-dependent exocytosis at step(s) distal to calcium influx. These results demonstrate that sympathetic nerves in the rabbit eye contain prejunctional, facilitatory AII receptors, and support the possible involvement of the renin-angiotensin system in regulation of ocular sympathetic neurotransmission in vivo.
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Affiliation(s)
- J E Jumblatt
- Department of Ophthalmology and Visual Sciences, Kentucky Lions Eye Research Institute, University of Louisville School of Medicine 40292
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Karnezis TA, Murphy MB, Weber RR, Nelson KS, Tripathi BJ, Tripathi RC. Effects of selective dopamine-1 receptor activation on intraocular pressure in man. Exp Eye Res 1988; 47:689-97. [PMID: 2904373 DOI: 10.1016/0014-4835(88)90036-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The lack of specific agonists and antagonists has, until recently, precluded investigation of a role for dopamine receptors in the control of intraocular pressure. In the present study, we have examined the effects of fenoldopam, a novel selective dopamine1 (DA1) receptor agonist, on intraocular pressure, in eight healthy human volunteers. Fenoldopam, infused intravenously at 0.5 micrograms kg-1 min-1, increased intraocular pressure from 14.6 +/- 0.9 to 17.6 +/- 1.4 mmHg (P less than 0.05) while a control saline infusion had no effect. Pupil diameter and blood pressure did not change. In the same subjects, i.v. norepinephrine or angiotensin II both increased intraocular pressure--from 13.8 +/- 1.4- to 17.6 +/- 1.4 mmHg and from 13.4 +/- 1.3- to 17.5 +/- 1.7 mmHg respectively (P less than 0.05), and mean arterial pressure by about 20 mmHg. These data suggest that: (1) DA1 receptor activation can modulate intraocular pressure; (2) the intraocular pressure effects of the DA1 receptor agonist, fenoldopam, are independent of changes in systemic blood pressure, in contrast to those of norepinephrine or angiotensin II where intraocular and systemic blood pressures increase in parallel; (3) the ability of a DA1 receptor antagonist to lower intraocular pressure merits investigation.
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Affiliation(s)
- T A Karnezis
- Committee on Clinical Pharmacology, University of Chicago, IL 60637
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Gherezghiher T, Hey JA, Koss MC. Systemic blood pressure and intraocular pressure relationship. JOURNAL OF OCULAR PHARMACOLOGY 1988; 4:291-301. [PMID: 3073175 DOI: 10.1089/jop.1988.4.291] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The relationship between intraocular pressure (IOP) and arterial blood pressure (BP) was analyzed in response to two pressor agents (norepinephrine and angiotensin II) and two depressor agents (methacholine and isoproterenol) in pentobarbital anesthetized cats. Both IOP and BP were measured manometrically in the same animals. Intravenous norepinephrine and angiotensin II produced dose-dependent increases, whereas intravenous methacholine and isoproterenol produced dose-dependent decreases of both BP and IOP. The IOP response to methacholine was biphasic, with an initial decrease followed by an increase above the pre-drug level. In some experiments a cannula loop was inserted into a carotid artery in order to separate the direct ocular effect of drugs on IOP from that contributed by the changes in systemic BP. Intravenous administration of norepinephrine and angiotensin II produced a larger increase in IOP on the side where drugs were delayed by the loop. Conversely, methacholine produced a larger fall in IOP on the cannulated side while the effect of isoproterenol was essentially unchanged. In other experiments injections were made directly into the ocular arterial blood supply. Norepinephrine and angiotensin II produced a decrease in IOP, methacholine produced a rise of IOP and isoproterenol was not active by this route. The present findings indicate that IOP is largely influenced by arterial BP changes in the acute phase and that the IOP response to drugs is the algebraic sum of effects on systemic BP and their direct ocular effects.
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Affiliation(s)
- T Gherezghiher
- Department of Ophthalmology, Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City
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Bell DR, Hollingsworth SF, Overbeck HW. Decreased intraocular pressure in dogs with one-kidney, one wrapped hypertension. Hypertension 1987; 10:152-6. [PMID: 3038745 DOI: 10.1161/01.hyp.10.2.152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We examined the relationship of intraocular pressure and the development of one-kidney, one wrapped (perinephritic) hypertension in the dog. Conscious femoral arterial pressure (direct arterial puncture) and intraocular pressure (Schiotz tonometer) were measured weekly before and after the surgical induction of hypertension in 11 healthy male mongrel dogs and before and after unilateral nephrectomy in 15 normotensive control dogs. Preoperative mean arterial pressure (102 +/- 5 vs 99 +/- 8 [SD] mm Hg, hypertensive vs control dogs) and intraocular pressure (18.1 +/- 2.5 vs 17.7 +/- 2.1 mm Hg, hypertensive vs control dogs) were similar in both groups. In normotensive control dogs, mean arterial pressure and intraocular pressure averaged over the postoperative period (4-8 weeks) did not differ significantly from preoperative values. In contrast, during the same period arterial pressure significantly increased and intraocular pressure significantly decreased in hypertensive dogs (arterial pressure, 163 +/- 8 mm Hg; intraocular pressure, 11.9 +/- 4.0 mm Hg; p less than 0.001 for both values compared with corresponding values in control dogs). Intraocular pressure was inversely related to arterial pressure in hypertensive dogs (r = 0.56, p less than 0.01). These observations indicate that intraocular pressure decreases with the development of canine one-kidney, one wrapped hypertension. The mechanism of this decrease may be related to abnormalities in Na+,K+-adenosine triphosphatase activity found in this form of hypertension.
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