Endothelin-1 effects on spontaneous oscillations in choroidal arterioles
| Autor: | Isabel Rocha, José Sales-Luís, Luis Silva-Carvalho, Esmeralda Delgado, Carlos Marques-Neves |
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| Přispěvatelé: | Repositório da Universidade de Lisboa |
| Rok vydání: | 2009 |
| Předmět: |
Male
medicine.medical_specialty Choroidal vasomotion Contraction (grammar) Time Factors Vasomotion Vasodilation In Vitro Techniques Internal medicine Oscillometry medicine Animals Isolated perfused rabbit eye Spontaneous oscillations Endothelin-1 Fourier Analysis Chemistry Choroid General Medicine Endothelin 1 Pressure sensor Vitreous Body Ophthalmology Arterioles medicine.anatomical_structure Injections Intra-Arterial Vasoconstriction Anesthesia Intraluminal pressure Pulsatile Flow Vascular resistance Cardiology Female Vascular Resistance Rabbits Injections Intraocular Perfusion |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| ISSN: | 1755-3768 |
| Popis: | © 2009 The Authors Journal compilation © 2009 Acta Ophthalmol Purpose: This study characterizes the effects of endothelin-1 (ET-1) on the perfusion pressure of the choroidal vasculature using in situ perfused isolated rabbit eyes. Methods: Rabbit external ophthalmic arteries (n = 12) in a head-mounted preparation were cannulated and perfused with warmed tyrode. The three-way polypropylene catheter was further connected to a pressure transducer and the effect of intraluminal pressure as a measure of total vascular resistance was assessed. Response curves to intra-arterial injections of ET-1 (group A; n = 6) and to an intravitreal injection followed by an intra-arterial injection of ET-1 (group B; n = 6) were obtained. Data were studied using paired t-test and fast Fourier transform. Results: Before any drugs were administered, spontaneous oscillations were observed in the 12 rabbit models. In group A, ET-1 induced a short and weak vasodilating effect followed by a strong and long-lasting vasoconstrictor tone. Vasomotion became more evident, showing a higher frequency and shorter amplitude of oscillations. In group, B the intravitreal injection produced no significant changes in registered pressure or vasomotion characteristics. The intra-arterial injection produced effects similar to those observed in group A. Conclusion: Our study has three main findings: (i) the choroidal vasculature demonstrated spontaneous oscillations in perfusion pressure in basal conditions in all rabbit eye models; (ii) ET-1 applied intra-arterially induced a short drop in perfusion pressure followed by a long withstanding contraction; and (iii) intra-arterial ET-1 modulated the frequency and amplitude of the spontaneous oscillations, causing a faster rate of pulsatility. This work was supported by Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA) |
| Databáze: | OpenAIRE |
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