title: Non-adrenergic sympathetic vasoconstriction in the eye and some other facial tissues in the rabbit.
abstract: The effects of unilateral sympathetic nerve stimulation (SNS) on regional blood flow in the rabbit were studied with radioactive microspheres. SNS at 10 or 4 Hz caused an approximately 60% reduction in choroidal blood flow, which was partly resistant to alpha-adrenoceptor blockade with phenoxybenzamine. The vasoconstriction evoked by SNS at 2 Hz was completely abolished by alpha-adrenoceptor blockade. A similar response was seen in the iris, ciliary body, masseter muscle and lacrimal gland. In the harderian gland, however, SNS (2 Hz) after alpha-adrenoceptor blockade caused a significant reduction in blood flow. In the salivary glands, combined beta- and alpha-adrenoceptor blockade with propranolol and phenoxybenzamine revealed a slight non-adrenergic vasoconstriction during SNS at 10 Hz; however, the blood flow was significantly increased during SNS at 4 and 2 Hz following alpha-adrenoceptor blockade. These results indicate that there is a frequency-dependent, non-adrenergic component in the sympathetic vasoconstriction of the eye and several facial tissues. In the salivary glands, beta-adrenoceptor-mediated vasodilatation tends to mask a non-adrenergic vasoconstriction.
authors.affiliation: Department of Physiology and Medical Biophysics, University of Uppsala, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Granstam
authors.forename: S F
authors.initials: SF
authors.lastname: Nilsson
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D002829:Choroid / Q000098:blood supply; D002924:Ciliary Body / Q000098:blood supply; D004558:Electric Stimulation; D005123:Eye / Q000098:blood supply*; D005145:Face / Q000098:blood supply*; D005260:Female; D006243:Harderian Gland / Q000098:blood supply; D007498:Iris / Q000098:blood supply; D007765:Lacrimal Apparatus / Q000098:blood supply; D008297:Male; D008406:Masseter Muscle / Q000098:blood supply; D011817:Rabbits; D012469:Salivary Glands / Q000098:blood supply; D013564:Sympathetic Nervous System / Q000187:drug effects; D014602:Uvea / Q000098:blood supply; D014661:Vasoconstriction
chemical_list: D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists