P2-purinergic receptor antagonists reduce the minimum alveolar concentration of inhaled volatile anesthetics

In the central nervous system (CNS), adenosine triphosphate (ATP) is report ed to serve as a fast excitatory neurotransmitter via P2X receptor. To exam ine possible involvement of inhibition of ATP signal-transmission in anesth etic mechanism, the effect of intracerebroventricular (ICV) administration of PZ receptor antagonists on the minimum alveolar concentration (MAC) of s evoflurane and isoflurane was studied in rat. ICV administration of P2 rece ptor antagonists, suramin and pyridoxal-phosphate-6-azophenyl-2',4'-disulph onic acid (PPADS), significantly reduced MAC of both anesthetics. The reduc tion of the MAC by both suramin and PPADS was dose-dependent and reached pl ateau at 150 mu g/rat. These results suggest that the inhibition of ATP-sig nal transmission may be involved in analgesic or anesthetic effect in brain . (C) 2000 Elsevier Science B.V. All rights reserved.