Postjunctional adrenergic receptors in the rabbit eye: effects on uveal flow and intraocular pressure in isolated arterially perfused eyes.
In uveal vessels of isolated arterially perfused rabbit eyes there is direct evidence for the presence of post-junctional alpha 1-receptors and indirect evidence for alpha 2-receptors. Since vasoconstriction by epinephrine could not be blocked by an alpha 1-antagonist, only 30% by an alpha 2-antagonist and almost fully by the combination or by phentolamine, we suggest the presence of an intermediate alpha-type receptor which is neither alpha 1 nor alpha 2 but has characteristics of either. All alpha-types produce vasoconstriction and a fall in IOP. Of the beta-types only beta 1-receptors can be demonstrated. They mediate vasodilatation and a rise in IOP. Neither beta 2- nor non-selective beta-agonists or -antagonists (e.g. timolol) affect IOP or uveal flow.
van Pinxteren
P C
PC
van Alphen
G W
GW
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001337:Autonomic Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D014602:Uvea / Q000098:blood supply*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D001337:Autonomic Agents