RESPONSE OF NASAL BLOOD-FLOW TO NEUROHORMONES AS MEASURED BY LASER-DOPPLER VELOCIMETRY

Laser-Doppler velocimetry (LDV) was adapted to measure nasal blood flow (NBF) in the mucosa of human volunteers. Resting NBF was 42.4 .+-. 2.1 ml .cntdot. 100 g-1 min-1 in 19 nonatopic subjects and 37.9 .+-. 1.7 ml .cntdot. 100 g-1 .cntdot. min-1 in 24 atopic subjects. Topical saline, but not water, reduced ipsilateral NBF by 15.4 .+-. 6.6% (n = 22) without affecting contralateral NBF. Administration of 60 .mu.g of oxymetazoline reduced NBF by 26.5% (n = 28), whereas 120 .mu.g resulted in a 54.3% reduction. Phenylephrine produced a dose-related reduction in NBF with an ID50 (dose producing 50% reduction) of 1456 .mu.g. Methacholine (0.006 to 12 mg) had no significant effect on NBF when studied alone or after oxymetazoline pretreatment. LDV can be employed to monitor NBF, which was found to be sensitive to .alpha.-adrenergic, but not cholinergic, stimulation.