Anesthesia and analgesia
-
Anesthesia and analgesia · Dec 2000
Comparative StudyRecovery from myocardial stunning is faster with desflurane compared with propofol in chronically instrumented dogs.
Volatile anesthetics exert a protective role in myocardial ischemia. An increase in sympathetic tone might exert deleterious effects on the ischemic myocardium. The use of the volatile anesthetic desflurane in myocardial ischemia is controversial because of its sympathetic activation. ⋯ Mean arterial pressure and heart rate were greater during ischemia and the first 10 min of reperfusion in the desflurane group compared with the propofol group. Recovery from myocardial stunning in dogs was faster when desflurane was used at the time of ischemia as compared with propofol anesthesia. The mechanism for this difference is unclear, but sympathetic activation by desflurane was not a limiting factor for ischemic tolerance in chronically instrumented dogs.
-
Anesthesia and analgesia · Dec 2000
Block of neuronal tetrodotoxin-resistant Na+ currents by stereoisomers of piperidine local anesthetics.
Tetrodotoxin (TTX)-sensitive Na(+) channels in the peripheral nervous system are the major targets for local anesthetics. In the peripheral nociceptive system, a Na(+) channel subtype resistant to TTX and with distinct electrophysiological properties seems to be of importance for impulse generation and conduction. A current through TTX-resistant Na(+) channels displays slower activation and inactivation kinetics and has an increased activation threshold compared with TTX-sensitive Na(+) currents and may have different pharmacological properties. ⋯ Potencies for tonic and for use-dependent block increased with rising lipid solubilities of the drugs. Stereoselective action was not observed. We conclude that block of TTX-resistant Na(+) currents may lead to blockade of TTX-resistant action potentials in nociceptive fibers and consequently may be responsible for pain suppression during local anesthesia.