title: Changes in choroidal blood flow during light/dark transitions are not altered by atropine or propranolol in healthy subjects.
abstract: It has recently been reported that light/dark transitions lead to changes in choroidal blood flow. Several observations indicate that these changes in choroidal perfusion are triggered at least in part by neural mechanisms. In the present study we hypothesised that the choroidal blood flow response to changes in retinal illumination may be modified by either the muscarinic receptor antagonist atropine or by the beta-receptor antagonist propranolol. In 15 healthy subjects the response of choroidal perfusion was studied in a randomised placebo-controlled three way cross-over study using laser Doppler flowmetry and laser interferometric measurement of fundus pulsation amplitude. Before drug administration a transition from light to dark reduced both choroidal haemodynamic parameters by 8%-12%. Neither propranolol nor atropine altered basal choroidal blood flow or choroidal blood flow responses to light/dark transitions. Our data indicate that neither muscarinic nor beta-receptors are involved in the choroidal blood flow response to changes in retinal illumination. Further studies are required to elucidate which mechanisms contribute to this blood flow behaviour of the choroid.
authors.affiliation: Department of Clinical Pharmacology, University of Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Fuchsjäger-Mayrl
authors.forename: Magdalena
authors.initials: M
authors.lastname: Malec
authors.forename: Tina
authors.initials: T
authors.lastname: Amoako-Mensah
authors.forename: Julia
authors.initials: J
authors.lastname: Kolodjaschna
authors.forename: Leopold
authors.initials: L
authors.lastname: Schmetterer
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D001285:Atropine / Q000494:pharmacology; D002829:Choroid / Q000098:blood supply*; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008027:Light; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010775:Photic Stimulation; D011433:Propranolol / Q000494:pharmacology; D012039:Regional Blood Flow; D012160:Retina / Q000502:physiology
chemical_list: D018727:Muscarinic Antagonists; D001285:Atropine; D011433:Propranolol