title: Ocular effects of alpha 2-adrenoceptor activation in anesthetized cats.
abstract: The present study was undertaken to determine the effects of direct administration of the selective alpha 2-adrenoceptor stimulant, B-HT 933, on choroidal blood flow, intraocular pressure and pupil size in anesthetized cats. Anterior segment choroidal blood flow was measured using laser-Doppler flowmetry. B-HT 933 administered by intra-arterial, topical and intracameral routes produced a significant depression of ocular blood flow which was largely abolished by pretreatment with rauwolscine. B-HT 933 did not lower IOP in any of these preparations. The largest doses of B-HT 933 caused a modest mydriasis when given intracamerally. However, this pupillary dilation was not blocked by rauwolscine. These results demonstrate that alpha 2-adrenoceptor activation can produce pronounced depression of anterior segment choroidal blood flow but does not cause a concomitant lowering of IOP or mydriasis in anesthetized cats.
authors.affiliation: Department of Pharmacology, University of Oklahoma College of Medicine, Oklahoma City.
authors.forename: M C
authors.initials: MC
authors.lastname: Koss
authors.forename: T
authors.initials: T
authors.lastname: Gherezghiher
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001381:Azepines / Q000008:administration & dosage / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects; D002415:Cats; D002829:Choroid / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D011680:Pupil / Q000187:drug effects*
chemical_list: D000316:Adrenergic alpha-Agonists; D001381:Azepines; C015603:azepexole