a site on a cell that, upon interaction with epinephrine or norepinephrine, controls vasoconstriction, intestinal relaxation, pupil dilation, and other physiological processes.
alpha-adrenergic receptor n.
Any of various cell membrane receptors that can bind with norepinephrine and related substances that activate or block the actions of the cells containing such receptors; these cells initiate physiological responses such as vasoconstriction, pupil dilation, and contraction of pilomotor muscles. Also called alpha-receptor.
- Alpha and omega
the beginning and the end. Rev. 1:8. the basic or essential element or elements: the alpha and omega of political reform. noun the first and last, a phrase used in Revelation 1:8 to signify God’s eternity the basic reason or meaning; most important part alpha and omega [(al-fuh; oh-may-guh, oh-meg-uh, oh-mee-guh)] The beginning and the […]
- Alpha angle
alpha angle alpha angle n. The angle between the visual and the optic axes as they cross at the nodal point of the eye. The angle between the visual line and the major axis of the corneal ellipse.
- Alpha axp 21164
alpha axp 21164 processor A 1 GIPS version of the DEC Alpha processor. The first commercially available sequential 1 GIPS processor. Announced 1994-09-7. (http://digital.com/info/semiconductor/dsc-21164.html). (1995-05-10)
- Alpha-beta brass
an alloy of from 55 to 61 percent copper with from 39 to 45 percent zinc.