title: Noradrenaline Improves Behavioral Contrast Sensitivity via the β-Adrenergic Receptor.
abstract: Noradrenaline (NA) is released from the locus coeruleus in the brainstem to almost the whole brain depending on the physiological state or behavioral context. NA modulates various brain functions including vision, but many questions about the functional role of its effects and mechanisms remain unclear. To explore these matters, we focused on three questions, 1) whether NA improves detectability of a behavior-relevant visual stimulus, 2) which receptor subtypes contribute to the NA effects, and 3) whether the NA effects are specific for visual features such as spatial frequency (SF). We measured contrast sensitivity in rats by a two-alternative forced choice visual detection task and tested the effects of NA receptor blockers in three SF conditions. Propranolol, a β-adrenergic receptor inhibitor, significantly decreased contrast sensitivity, but neither prazosin nor idazoxan, α1- and α2-adrenergic receptor inhibitors, respectively, had an effect. This β blocker effect was observed only at optimal SF. These results indicate that endogenous NA enhances visual detectability depending on stimulus spatial properties via mainly β-adrenergic receptors.
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Frontier Bioscience, Osaka University, Suita, Osaka, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Mizuyama
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Medicine, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Soma
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Medicine, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Suemastu
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Frontier Bioscience, Osaka University, Suita, Osaka, Japan.|Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Medicine, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shimegi
mesh_terms: D000818:Animals; D015350:Contrast Sensitivity / Q000187:drug effects / Q000502:physiology*; D019329:Idazoxan / Q000494:pharmacology; D008125:Locus Coeruleus / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D010775:Photic Stimulation; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
chemical_list: D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin; D019329:Idazoxan