- 1. A turning or changing to the opposite direction, as of a process, disease, symptom, or state. 2. The changing of a dark line or a bright one of the spectrum into its opposite. 3. Denoting the difficulty of some persons in distinguishing the lowercase printed or written letter p from q or g, b from d, or s from z. 4. In psychoanalysis, the change of an instinct or affect into its opposite, as from love into hate. [L. reverto, pp. -versus, to turn back or about]- adrenaline r. SYN: epinephrine r..- epinephrine r. the fall in blood pressure produced by epinephrine when given following blockage of α-adrenergic receptors by an appropriate drug such as phenoxybenzamine; the vasodilation reflects the ability of epinephrine to activate β-adrenergic receptors that, in vascular smooth muscle, are inhibitory; in the absence of α-receptor blockade, the β-receptor activation by epinephrine is masked by its predominant action on vascular α-receptors, which causes vasoconstriction. SYN: adrenaline r..- narcotic r. the use of narcotic antagonists, such as naloxone, to terminate the action of narcotics.- pressure r. cessation of anesthesia by hyperbaric pressure; of major importance in understanding the mode of action of anesthetics.- sex r. SYN: sex reassignment.
* * *re·ver·sal ri-'vər-səl n an act or the process of reversing
* * *re·ver·sal (re-vurґsəl) a turning or change to go in the opposite direction.
Medical dictionary. 2011.