The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
José Melena - One of the best experts on this subject based on the ideXlab platform.
-
A comparative study of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in oclular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits
Graefe's Archive for Clinical and Experimental Ophthalmology, 2007Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported that topical natural ergot alkaloids Ergocristine α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to compare the effect of Ergocristine, α-ergocryptine and ergocornine on the intraocular pressure and aqueous humor dynamics in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, in order to further explore the ocular actions of these compounds. Methods Experiments were conducted in albino ocular normotensive and hypertensive rabbits by intracameral injection of α-chymotrypsin. Intraocular pressure responses to drug vehicle and seven different doses of topical natural ergot alkaloids were examined, in order to obtain dose–response relationships for comparing the intraocular pressure-lowering effect and potency of these drugs. Tonographies were also performed to ascertain the actions of natural ergot alkaloids on aqueous humor dynamics. Results All natural ergot alkaloids tested reduced intraocular pressure in a dose-related fashion. The ocular hypotensive effect was greater in α-chymotrypsin-induced ocular hypertensive rabbits for the three compounds tested. All natural ergot alkaloids tested decreased both tonographic outflow facility and, to a greater extent, aqueous humor inflow in ocular normotensive and in α-chymotrypsin-induced ocular hypertensive rabbits. Conclusion Taken together, our data suggest that these compounds decrease both tonographic outflow facility and, to a greater extent, aqueous humor inflow, which explains their final effect in ocular normotensive and in α-chymotrypsin-induced ocular hypertensive rabbits. Reductions in aqueous humor inflow observed after topical application of natural ergot alkaloids in α-chymotrypsin-induced ocular hypertensive rabbits can only be explained by a marked inhibition of active secretion of aqueous humor, since processes involved in aqueous humor formation may probably be altered after α-chymotrypsin injection.
-
A comparative study of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in oclular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits
Graefes Archive for Clinical and Experimental Ophthalmology, 2007Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported that topical natural ergot alkaloids Ergocristine α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to compare the effect of Ergocristine, α-ergocryptine and ergocornine on the intraocular pressure and aqueous humor dynamics in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, in order to further explore the ocular actions of these compounds.
-
The effect of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in rabbits with α-chymotrypsin-induced ocular hypertension
Graefe's Archive for Clinical and Experimental Ophthalmology, 2002Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background: We previously reported that topical natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive rabbits, most likely by decreasing aqueous humor inflow. In the present study, the effects of these compounds on intraocular pressure and aqueous humor dynamics in a rabbit model for ocular hypertension were assessed. Methods: Experiments were conducted in albino rabbits made ocular hypertensive by intracameral injection of α-chymotrypsin. Intraocular pressure responses to drug vehicle and seven different doses of topical natural ergot alkaloids were examined in order to obtain dose–response relationships for comparing the intraocular pressure-lowering effect and potency of these drugs. Tonographies were also performed to ascertain the actions of natural ergot alkaloids on aqueous humor dynamics in α-chymotrypsin-induced ocular hypertensive rabbits. Results: Topical application of the natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine lowered intraocular pressure in α-chymotrypsin-induced ocular hypertensive rabbits in a dose-related fashion, with Ergocristine displaying the greatest intraocular pressure-lowering effect. Tonographic studies revealed a decrease in the tonographic outflow facility following topical application of natural ergot alkaloids, although only the effects of both Ergocristine and α-ergocryptine reached statistical significance. All natural ergot alkaloids tested significantly reduced the calculated aqueous humor inflow. Conclusion: This study suggests that the natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine effectively decrease intraocular pressure in the α-chymotrypsin-induced model of ocular hypertension. Since these compounds reduce the tonographic aqueous humor outflow facility, their final ocular antihypertensive effect appears to result from a remarkable reduction of the aqueous humor inflow.
-
Effects of Topical Natural Ergot Alkaloids on Intraocular Pressure and Aqueous Humor Dynamics in Ocular Normotensive Rabbits
Journal of Ocular Pharmacology and Therapeutics, 2002Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported in our laboratory that topical dihydroErgocristine decreases intraocular pressure both in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to assess the effect of natural ergot alkaloids, Ergocristine, α-ergocryptine and ergocornine, on the intraocular pressure and aqueous humor dynamics in ocular normotensive rabbits in order to further explore the ocular actions of these compounds. Intraocular pressure was measured with a pneumatonometer manometrically calibrated for the rabbit eye. Changes in tonographic facility of aqueous humor outflow and rate of aqueous humor inflow were evaluated in anesthetized rabbits. Natural ergot alkaloids were found to reduce intraocular pressure in ocular normotensive eyes in a dose-related fashion. These compounds de...
Hans-ulrich Humpf - One of the best experts on this subject based on the ideXlab platform.
-
Localization of ergot alkaloids in sclerotia of Claviceps purpurea by matrix-assisted laser desorption/ionization mass spectrometry imaging
Analytical and Bioanalytical Chemistry, 2017Co-Authors: Julian Dopstadt, Simeon Vens-cappell, Lisa Neubauer, Paul Tudzynski, Benedikt Cramer, Klaus Dreisewerd, Hans-ulrich HumpfAbstract:The fungus Claviceps purpurea produces highly toxic ergot alkaloids and accumulates these in the hardened bodies of fungal mycelium. These so-called sclerotia, or ergot bodies, replace the crop seed of infected plants, which can include numerous important food- and feedstuff such as rye and wheat. While several studies have explored details of the infection process and development of ergot bodies, little information is available on the spatial distribution of the mycotoxins in the sclerotia. Here we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) at a lateral resolution of 35 μm to visualize the distribution of two representative alkaloids, Ergocristine and ergometrine, produced by Ecc93 and Gal 310 variants of C. purpurea , respectively, after infection of rye. To improve cryosectioning of this fragile biological material tissue with complex texture, we developed a practical embedding protocol based on cellulose polymers. The MALDI-MS images recorded from the so produced intact tissues sections revealed that ergometrine exhibited a relatively homogeneous distribution throughout the ergot body, whereas Ergocristine was found to be enriched in the proximal region. This finding can be correlated to the morphological development of sclerotia as ergot alkaloids are only produced in the sphacelial stage. The ability to localize toxins and other secondary metabolites in intact sections of crop-infecting fungi with high lateral resolution renders MALDI-MSI a powerful tool for investigating biosynthetic pathways and for obtaining a deeper understanding of the parasite-host interaction. Graphical abstract Workflow for identification and spatial localization of ergot alkaloids in infected rye grains
-
Localization of ergot alkaloids in sclerotia of Claviceps purpurea by matrix-assisted laser desorption/ionization mass spectrometry imaging
Analytical and Bioanalytical Chemistry, 2016Co-Authors: Julian Dopstadt, Simeon Vens-cappell, Lisa Neubauer, Paul Tudzynski, Benedikt Cramer, Klaus Dreisewerd, Hans-ulrich HumpfAbstract:The fungus Claviceps purpurea produces highly toxic ergot alkaloids and accumulates these in the hardened bodies of fungal mycelium. These so-called sclerotia, or ergot bodies, replace the crop seed of infected plants, which can include numerous important food- and feedstuff such as rye and wheat. While several studies have explored details of the infection process and development of ergot bodies, little information is available on the spatial distribution of the mycotoxins in the sclerotia. Here we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) at a lateral resolution of 35 μm to visualize the distribution of two representative alkaloids, Ergocristine and ergometrine, produced by Ecc93 and Gal 310 variants of C. purpurea, respectively, after infection of rye. To improve cryosectioning of this fragile biological material tissue with complex texture, we developed a practical embedding protocol based on cellulose polymers. The MALDI-MS images recorded from the so produced intact tissues sections revealed that ergometrine exhibited a relatively homogeneous distribution throughout the ergot body, whereas Ergocristine was found to be enriched in the proximal region. This finding can be correlated to the morphological development of sclerotia as ergot alkaloids are only produced in the sphacelial stage. The ability to localize toxins and other secondary metabolites in intact sections of crop-infecting fungi with high lateral resolution renders MALDI-MSI a powerful tool for investigating biosynthetic pathways and for obtaining a deeper understanding of the parasite-host interaction.
-
Cytotoxicity and accumulation of ergot alkaloids in human primary cells
Toxicology, 2011Co-Authors: Dennis Mulac, Hans-ulrich HumpfAbstract:Abstract Ergot alkaloids are secondary metabolites produced by fungi of the species Claviceps . Toxic effects after consumption of contaminated grains are described since mediaeval times. Of the more than 40 known ergot alkaloids six are found predominantly. These are ergotamine, ergocornine, ergocryptine, Ergocristine, ergosine and ergometrine, along with their corresponding isomeric forms (-inine-forms). Toxic effects are known to be induced by an interaction of the ergot alkaloids as neurotransmitters, like dopamine or serotonin. Nevertheless data concerning cytotoxic effects are missing and therefore a screening of the six main ergot alkaloids was performed in human primary cells in order to evaluate the toxic potential. As it is well known that ergot alkaloids isomerize easily the stability was tested in the cell medium. Based on these results factors were calculated to correct the used concentration values to the biologically active lysergic (-ine) form. These factors range from 1.4 for the most stable compound ergometrine to 5.0 for the most unstable ergot alkaloid Ergocristine. With these factors, reflecting the instability, several controverse literature data concerning the toxicity could be explained. To evaluate the cytotoxic effects of ergot alkaloids, human cells in primary culture were used. These cells remain unchanged in contrast to cell lines and the data allow a better comparison to the in vivo situation than using immortalized cell lines. To characterize the effects on primary cells, renal proximal tubule epithelial cells (RPTEC) and normal human astrocytes (NHA) were used. The parameters necrosis (LDH-release) and apoptosis (caspase-3-activation, DNA condensation and fragmentation) were distinguished. The results show that depending on the individual structure of the peptide ergot alkaloids the toxic properties change. While ergometrine as a lysergic acid amide did not show any effect, the peptide ergot alkaloids revealed a different toxic potential. Of all tested ergot alkaloids Ergocristine was the most cytotoxic compound inducing apoptosis in human kidney cells starting at a concentration of 1 μM in RPTEC. Uptake studies underline the cytotoxic properties, with an accumulation of peptide ergot alkaloids and no uptake of ergometrine. The results represent a new description of effects of ergot alkaloids regarding cytotoxicity and accumulation in human primary cells. For the first time apoptosis has been identified besides well described receptor effects. This gives a hint for a more complex mode of action of ergot alkaloids than described in literature so far.
-
Ricinoleic Acid as a Marker for Ergot Impurities in Rye and Rye Products
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Carolin Franzmann, Johannes Wächter, Natascha Dittmer, Hans-ulrich HumpfAbstract:Ergot alkaloid and ricinoleic acid contents of 63 ergot sclerotia samples from rye throughout Germany of the harvest years 2006−2009 were determined. Alkaloid contents were analyzed by means of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and ricinoleic acid contents by means of gas chromatography with flame ionization detection (GC-FID). Ergot alkaloid amounts ranged from 0.01 to 0.2 g/100 g of sclerotia with an average amount of 0.08 g/100 g. Ergotamine and Ergocristine were identified as lead alkaloids representing 57% (w/w) of the total alkaloid content. The average ricinoleic acid amount in the ergot sclerotia was 10.3 g/100 g. Because of the low variation of ricinoleic acid content in the ergot sclerotia, a new method for the determination of ricinoleic acid in rye products as a marker for ergot contaminations was developed. This method allows the determination of ergot impurities as low as 0.01% (w/w). Furthermore, 29 rye products (flours, bread mix, bread) were inv...
H. Graf V. Reichenbach - One of the best experts on this subject based on the ideXlab platform.
-
Zum Einfluss einer hydrothermischen Behandlung auf den Ergotalkaloidgehalt von mutterkornbelastetem Roggen
Mycotoxin Research, 2005Co-Authors: Simone Mainka, Sven Dänicke, Karl-heinz Ueberschär, H. Graf V. ReichenbachAbstract:Hydrothermal treatments are primarily used to increase the digestibility of nutrients and therefore to improve the feeding value of feedstuffs mainly for non-ruminants. Other positive side effects may occur, e.g. a decrease in toxicity of feed contaminated with mycotoxins. To study such effects, 4 batches of rye containing different percentages (0.8, 4.2, 8.3 and 25%) of ergot (Claviceps purpurea) were expanded and ergot alkaloid contents were analysed. After pre-conditioning of each batch by steam exposure for approx. 2 min, at 95 °C and 17% moisture, the material was expanded for approx. 5 sec. at 120 °C, 18% moisture, 40 bar mechanical pressure and 20 kWh/t mechanical energy input. Samples were collected before and after pre-conditioning and after expanding. Ergot alkaloids were analysed by HPLC. Analysis includedErgometrine, Ergotamine, Ergocornine, Ergocryptine, Ergocristine, Ergosine and their respective-inine isomers, the sum of these 12 ergot alkaloids was referred to as the total alkaloid content.
-
Zum Einfluss einer hydrothermischen Behandlung auf den Ergotalkaloidgehalt von mutterkornbelastetem Roggen
Mycotoxin Research, 2005Co-Authors: S. Mainka, S. Dänicke, K. -h. Ueberschär, H. Graf V. ReichenbachAbstract:Hydrothermal treatments are primarily used to increase the digestibility of nutrients and therefore to improve the feeding value of feedstuffs mainly for non-ruminants. Other positive side effects may occur, e.g. a decrease in toxicity of feed contaminated with mycotoxins. To study such effects, 4 batches of rye containing different percentages (0.8, 4.2, 8.3 and 25%) of ergot ( Claviceps purpurea ) were expanded and ergot alkaloid contents were analysed. After pre-conditioning of each batch by steam exposure for approx. 2 min, at 95 °C and 17% moisture, the material was expanded for approx. 5 sec. at 120 °C, 18% moisture, 40 bar mechanical pressure and 20 kWh/t mechanical energy input. Samples were collected before and after pre-conditioning and after expanding. Ergot alkaloids were analysed by HPLC. Analysis included Ergometrine, Ergotamine, Ergocornine, Ergocryptine, Ergocristine, Ergosine and their respective- inine isomers, the sum of these 12 ergot alkaloids was referred to as the total alkaloid content. On average, the hydrothermal treatment (pre-conditioning and expanding) caused a decrease of the total ergot alkaloid content of approx. 10%. Except for the batch containing 0.8% ergot, the efficiency of the hydrothermal treatment decreased with increasing ergot concentration in the batches. In general, the hydrothermal treatment changed the proportions of the ergot alkaloid isomers since the percentages of the- inine isomers of the total ergot alkaloid contents were increased with reduced- ine percentages. Whether this alteration is of toxicological relevance should be evaluated in animal experiments.
Gustavo Puras - One of the best experts on this subject based on the ideXlab platform.
-
A comparative study of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in oclular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits
Graefe's Archive for Clinical and Experimental Ophthalmology, 2007Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported that topical natural ergot alkaloids Ergocristine α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to compare the effect of Ergocristine, α-ergocryptine and ergocornine on the intraocular pressure and aqueous humor dynamics in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, in order to further explore the ocular actions of these compounds. Methods Experiments were conducted in albino ocular normotensive and hypertensive rabbits by intracameral injection of α-chymotrypsin. Intraocular pressure responses to drug vehicle and seven different doses of topical natural ergot alkaloids were examined, in order to obtain dose–response relationships for comparing the intraocular pressure-lowering effect and potency of these drugs. Tonographies were also performed to ascertain the actions of natural ergot alkaloids on aqueous humor dynamics. Results All natural ergot alkaloids tested reduced intraocular pressure in a dose-related fashion. The ocular hypotensive effect was greater in α-chymotrypsin-induced ocular hypertensive rabbits for the three compounds tested. All natural ergot alkaloids tested decreased both tonographic outflow facility and, to a greater extent, aqueous humor inflow in ocular normotensive and in α-chymotrypsin-induced ocular hypertensive rabbits. Conclusion Taken together, our data suggest that these compounds decrease both tonographic outflow facility and, to a greater extent, aqueous humor inflow, which explains their final effect in ocular normotensive and in α-chymotrypsin-induced ocular hypertensive rabbits. Reductions in aqueous humor inflow observed after topical application of natural ergot alkaloids in α-chymotrypsin-induced ocular hypertensive rabbits can only be explained by a marked inhibition of active secretion of aqueous humor, since processes involved in aqueous humor formation may probably be altered after α-chymotrypsin injection.
-
A comparative study of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in oclular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits
Graefes Archive for Clinical and Experimental Ophthalmology, 2007Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported that topical natural ergot alkaloids Ergocristine α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to compare the effect of Ergocristine, α-ergocryptine and ergocornine on the intraocular pressure and aqueous humor dynamics in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, in order to further explore the ocular actions of these compounds.
-
The effect of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in rabbits with α-chymotrypsin-induced ocular hypertension
Graefe's Archive for Clinical and Experimental Ophthalmology, 2002Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background: We previously reported that topical natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive rabbits, most likely by decreasing aqueous humor inflow. In the present study, the effects of these compounds on intraocular pressure and aqueous humor dynamics in a rabbit model for ocular hypertension were assessed. Methods: Experiments were conducted in albino rabbits made ocular hypertensive by intracameral injection of α-chymotrypsin. Intraocular pressure responses to drug vehicle and seven different doses of topical natural ergot alkaloids were examined in order to obtain dose–response relationships for comparing the intraocular pressure-lowering effect and potency of these drugs. Tonographies were also performed to ascertain the actions of natural ergot alkaloids on aqueous humor dynamics in α-chymotrypsin-induced ocular hypertensive rabbits. Results: Topical application of the natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine lowered intraocular pressure in α-chymotrypsin-induced ocular hypertensive rabbits in a dose-related fashion, with Ergocristine displaying the greatest intraocular pressure-lowering effect. Tonographic studies revealed a decrease in the tonographic outflow facility following topical application of natural ergot alkaloids, although only the effects of both Ergocristine and α-ergocryptine reached statistical significance. All natural ergot alkaloids tested significantly reduced the calculated aqueous humor inflow. Conclusion: This study suggests that the natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine effectively decrease intraocular pressure in the α-chymotrypsin-induced model of ocular hypertension. Since these compounds reduce the tonographic aqueous humor outflow facility, their final ocular antihypertensive effect appears to result from a remarkable reduction of the aqueous humor inflow.
-
Effects of Topical Natural Ergot Alkaloids on Intraocular Pressure and Aqueous Humor Dynamics in Ocular Normotensive Rabbits
Journal of Ocular Pharmacology and Therapeutics, 2002Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported in our laboratory that topical dihydroErgocristine decreases intraocular pressure both in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to assess the effect of natural ergot alkaloids, Ergocristine, α-ergocryptine and ergocornine, on the intraocular pressure and aqueous humor dynamics in ocular normotensive rabbits in order to further explore the ocular actions of these compounds. Intraocular pressure was measured with a pneumatonometer manometrically calibrated for the rabbit eye. Changes in tonographic facility of aqueous humor outflow and rate of aqueous humor inflow were evaluated in anesthetized rabbits. Natural ergot alkaloids were found to reduce intraocular pressure in ocular normotensive eyes in a dose-related fashion. These compounds de...
Juan Santafé - One of the best experts on this subject based on the ideXlab platform.
-
A comparative study of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in oclular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits
Graefe's Archive for Clinical and Experimental Ophthalmology, 2007Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported that topical natural ergot alkaloids Ergocristine α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to compare the effect of Ergocristine, α-ergocryptine and ergocornine on the intraocular pressure and aqueous humor dynamics in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, in order to further explore the ocular actions of these compounds. Methods Experiments were conducted in albino ocular normotensive and hypertensive rabbits by intracameral injection of α-chymotrypsin. Intraocular pressure responses to drug vehicle and seven different doses of topical natural ergot alkaloids were examined, in order to obtain dose–response relationships for comparing the intraocular pressure-lowering effect and potency of these drugs. Tonographies were also performed to ascertain the actions of natural ergot alkaloids on aqueous humor dynamics. Results All natural ergot alkaloids tested reduced intraocular pressure in a dose-related fashion. The ocular hypotensive effect was greater in α-chymotrypsin-induced ocular hypertensive rabbits for the three compounds tested. All natural ergot alkaloids tested decreased both tonographic outflow facility and, to a greater extent, aqueous humor inflow in ocular normotensive and in α-chymotrypsin-induced ocular hypertensive rabbits. Conclusion Taken together, our data suggest that these compounds decrease both tonographic outflow facility and, to a greater extent, aqueous humor inflow, which explains their final effect in ocular normotensive and in α-chymotrypsin-induced ocular hypertensive rabbits. Reductions in aqueous humor inflow observed after topical application of natural ergot alkaloids in α-chymotrypsin-induced ocular hypertensive rabbits can only be explained by a marked inhibition of active secretion of aqueous humor, since processes involved in aqueous humor formation may probably be altered after α-chymotrypsin injection.
-
A comparative study of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in oclular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits
Graefes Archive for Clinical and Experimental Ophthalmology, 2007Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported that topical natural ergot alkaloids Ergocristine α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to compare the effect of Ergocristine, α-ergocryptine and ergocornine on the intraocular pressure and aqueous humor dynamics in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, in order to further explore the ocular actions of these compounds.
-
The effect of topical natural ergot alkaloids on the intraocular pressure and aqueous humor dynamics in rabbits with α-chymotrypsin-induced ocular hypertension
Graefe's Archive for Clinical and Experimental Ophthalmology, 2002Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Background: We previously reported that topical natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine dose-dependently reduce intraocular pressure in ocular normotensive rabbits, most likely by decreasing aqueous humor inflow. In the present study, the effects of these compounds on intraocular pressure and aqueous humor dynamics in a rabbit model for ocular hypertension were assessed. Methods: Experiments were conducted in albino rabbits made ocular hypertensive by intracameral injection of α-chymotrypsin. Intraocular pressure responses to drug vehicle and seven different doses of topical natural ergot alkaloids were examined in order to obtain dose–response relationships for comparing the intraocular pressure-lowering effect and potency of these drugs. Tonographies were also performed to ascertain the actions of natural ergot alkaloids on aqueous humor dynamics in α-chymotrypsin-induced ocular hypertensive rabbits. Results: Topical application of the natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine lowered intraocular pressure in α-chymotrypsin-induced ocular hypertensive rabbits in a dose-related fashion, with Ergocristine displaying the greatest intraocular pressure-lowering effect. Tonographic studies revealed a decrease in the tonographic outflow facility following topical application of natural ergot alkaloids, although only the effects of both Ergocristine and α-ergocryptine reached statistical significance. All natural ergot alkaloids tested significantly reduced the calculated aqueous humor inflow. Conclusion: This study suggests that the natural ergot alkaloids Ergocristine, α-ergocryptine and ergocornine effectively decrease intraocular pressure in the α-chymotrypsin-induced model of ocular hypertension. Since these compounds reduce the tonographic aqueous humor outflow facility, their final ocular antihypertensive effect appears to result from a remarkable reduction of the aqueous humor inflow.
-
Effects of Topical Natural Ergot Alkaloids on Intraocular Pressure and Aqueous Humor Dynamics in Ocular Normotensive Rabbits
Journal of Ocular Pharmacology and Therapeutics, 2002Co-Authors: Gustavo Puras, Juan Santafé, José Segarra, Manuel Garrido, José MelenaAbstract:Although it has been suggested that ergot derivatives may play a role in antiglaucoma therapy, little attention has been paid to the ocular hypotensive action of these drugs. Having previously reported in our laboratory that topical dihydroErgocristine decreases intraocular pressure both in ocular normotensive and α-chymotrypsin-induced ocular hypertensive rabbits, the aim of the present work was to assess the effect of natural ergot alkaloids, Ergocristine, α-ergocryptine and ergocornine, on the intraocular pressure and aqueous humor dynamics in ocular normotensive rabbits in order to further explore the ocular actions of these compounds. Intraocular pressure was measured with a pneumatonometer manometrically calibrated for the rabbit eye. Changes in tonographic facility of aqueous humor outflow and rate of aqueous humor inflow were evaluated in anesthetized rabbits. Natural ergot alkaloids were found to reduce intraocular pressure in ocular normotensive eyes in a dose-related fashion. These compounds de...