OBJECTIVETo evaluate the effect of intrathecal administration of glycine on the minimum alveolar concentration (MAC) of isoflurane in rats.

METHODSIntrathecal catheters were implanted in 40 adult male rats anesthetized with isoflurane. Baseline MAC of isoflurane was measured during the infusion of artificial cerebrospinal fluid (CSF) alone. Subsequently, 10, 40, 80, 160, and 300 mmol/L of glycine dissolved in artificial CSF were infused for two hours at the same rate as under control conditions, and MAC for isoflurane was re-determined.

RESULTSIntrathecal administration of glycine produced a significant, dose-dependent decrease in MAC for isoflurane (up to -65.2% +/- 16.2%).

CONCLUSIONSIntrathecal administration of glycine decreases anesthetic requirement This result supports the idea that glycine receptors may be important to the immobilizing effect of anesthetics that enhance glycine receptor function such as isoflurane.

Anesthetics, Inhalation ; metabolism ; Animals ; Glycine ; administration & dosage ; pharmacology ; Injections, Spinal ; Isoflurane ; metabolism ; Male ; Pulmonary Alveoli ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley