Adenosine
Small alterations of endogenous adenosine concentrations do not
substantially alter the anesthetic requirement
Figure 4-8
The D-stereoisomer (closed
squares) of the α2
-adrenergic agonist medetomidine causes
a dose-dependent decrease in the halothane minimum alveolar concentration (MAC) in
dogs, whereas the L-stereoisomer (open
squares) has little or no influence on halothane MAC. Asterisks
indicate values that are significantly different from the controls. (Adapted
from Vickery RG, Sheridan BC, Segal IS, et al: Anesthetic and hemodynamic effects
of the stereoisomers of medetomidine, an α2
-adrenergic agonist,
in halothane-anesthetized dogs. Anesth Analg 67:611, 1988.)
in dogs.[64]
Exogenous administration of adenosine
decreases the halothane MAC in dogs by about 50%,[64]
but adenosine (at doses that require vasopressors to maintain blood pressure) does
not alter the sevoflurane MAC or sevoflurane MAC-awake in patients.[65]
Although adenosine may prove helpful in providing relief from chronic pain, adenosine
does not alter response to acute noxious stimulation in humans.[66]
