Pre- and postsynaptic effects of brimonidine on isolated rabbit iris dilator muscles
| Autor: | Sonoko Tatsui, Kimiya Shimizu, Hitoshi Ishikawa, Kimiyo Mashimo |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
medicine.medical_specialty
Contraction (grammar) Neurotransmission 01 natural sciences 010104 statistics & probability Postsynaptic potential Ophthalmology Night vision 0502 economics and business rabbit iris dilator Medicine 0101 mathematics postsynaptic α1-adrenoceptor Phenylephrine Original Research 050205 econometrics brimonidine business.industry Brimonidine 05 social sciences Clinical Ophthalmology electrical field stimulation presynaptic α2-adrenoceptor Iris dilator muscle Dilator imidazolin business medicine.drug |
| Zdroj: | Clinical Ophthalmology (Auckland, N.Z.) |
| ISSN: | 1177-5483 |
| DOI: | 10.2147/opth.s100755 |
| Popis: | Sonoko Tatsui,1 Hitoshi Ishikawa,2 Kimiya Shimizu,1 Kimiyo Mashimo1 1Department of Ophthalmology, School of Medicine, Kitasato University, 2Department of Orthoptics and Visual Sciences, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan Purpose: Brimonidine is an imidazoline compound used for the treatment of glaucoma, but having very little effect on pupil diameter. Like para-aminoclonidine, most imidazoline compounds interact with postsynaptic α-adrenoceptors and cause pupil dilatation. Therefore, as part of an investigation of the mechanism of action of brimonidine on pupil diameter, the present study was initiated to measure, in vitro, the relative potency of brimonidine on the pre- and postsynaptic α-adrenoceptors of rabbit iris dilator muscle. Methods: The contractile activity of brimonidine and its effect on twitch contraction evoked by electrical field stimulation were studied in isolated rabbit iris dilator muscles by isometric tension recording. Results: Brimonidine significantly inhibited the twitch contraction of the dilator muscle caused by field stimulation, without affecting the response to exogenously applied phenylephrine. Compared to phenylephrine, brimonidine caused only a small contractile response with % maximum contraction values of |
| Databáze: | OpenAIRE |
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