α2-Adrenoceptors Do Not Mediate Reflex Mydriasis in Rabbits
| Autor: | Yongxin Yu, Michael C. Koss |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Male
medicine.medical_specialty Pentobarbital Phenoxybenzamine Models Neurological Stimulation Reflex Pupillary Receptors Dopamine Receptors Adrenergic alpha-2 Internal medicine medicine Mydriasis Adrenergic antagonist Animals Anesthesia Pharmacology (medical) Naphthyridines Sympathectomy Adrenergic alpha-Antagonists Pharmacology Dose-Response Relationship Drug Chemistry Antagonist Drug Synergism Adrenergic alpha-2 Receptor Antagonists Isoquinolines Sciatic Nerve Electric Stimulation Ophthalmology Endocrinology Injections Intravenous Reflex Dopamine Antagonists Haloperidol Rabbits Sciatic nerve medicine.symptom medicine.drug |
| Zdroj: | Journal of Ocular Pharmacology and Therapeutics. 20:479-488 |
| ISSN: | 1557-7732 1080-7683 |
| DOI: | 10.1089/jop.2004.20.479 |
| Popis: | The aim of this study was to identify receptors that mediate reflex mydriasis in pentobarbital-anesthetized rabbits, in which the cervical sympathetic nerve was sectioned unilaterally. Voltage-response curves of pupillary dilation were generated bilaterally by stimulation of the sciatic nerve. Evoked mydriatic responses were mediated mainly by efferent parasympathetic innervation, and, to a lesser extent, by sympathetic innervation. The alpha-adrenergic antagonist, phenoxybenzamine (0.3 mg/kg, intravenously (i.v.)), antagonized mydriasis of the neurally intact eye, but not that on the sympathectomized side. The alpha2-adrenergic antagonist, RS 79948 (0.3 mg/kg, i.v.), potentiated mydriasis of the normal eye, but was without either a potentiating or inhibitory effect on the mydriasis of the sympathectomized eye. In addition, the dopamine-receptor antagonist, haloperidol (1 mg/kg, i.v.), inhibited evoked mydriasis of the sympathectomized eye. These results suggest that, unlike some other species (cats and rats), alpha2-adrenoceptors do not mediate reflex mydriasis elicited by sciatic-nerve stimulation in the rabbit, and support the previous finding in humans that dopamine receptors may mediate this response. |
| Databáze: | OpenAIRE |
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