title: Cochlear microcirculation. Effect of adrenergic agonists on arteriole diameter.
abstract: We used intravital fluorescent microscopy coupled with computerized video image processing to examine the cochlear microvasculature. In Mongolian gerbils the bulla was opened ventrally and a small window was made in the second turn of the cochlea. After fluorescein isothiocyanate-dextran administration, the radiating arterioles were video-recorded under X675 magnification. Computer determinations of arteriolar response to norepinephrine bitartrate (mixed alpha 1/alpha 2 agonist), phenylephrine hydrochloride (alpha 1 agonist), and UK 14,304 tartrate (alpha 2 agonist) were made at multiple dose levels over time. Findings were consistent with arteriolar constriction in response to alpha-adrenergic stimulation. The presence of alpha 1 and alpha 2 receptors was established, and a predominance of alpha 2 receptors in the cochlea was suggested.
authors.affiliation: Division of Otolaryngology-Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill.
authors.forename: V N
authors.initials: VN
authors.lastname: Carrasco
authors.forename: J
authors.initials: J
authors.lastname: Prazma
authors.forename: J E
authors.initials: JE
authors.lastname: Faber
authors.forename: R J
authors.initials: RJ
authors.lastname: Triana
authors.forename: H C
authors.initials: HC
authors.lastname: Pillsbury
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000187:drug effects; D000068438:Brimonidine Tartrate; D003051:Cochlea / Q000098:blood supply* / Q000294:innervation; D005849:Gerbillinae; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D014743:Videotape Recording
chemical_list: D000316:Adrenergic alpha-Agonists; D011810:Quinoxalines; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D000068438:Brimonidine Tartrate; D009638:Norepinephrine