Nonlinear additivity of nitrous oxide and isoflurane potencies in rats
| Autor: | Garfield B. Russell, John M. Graybeal |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Male
Isoflurane business.industry Non linearite Rat model Nitrous Oxide Drug Synergism General Medicine Nitrous oxide equipment and supplies Rats Pulmonary Alveoli chemistry.chemical_compound Long evans rats Anesthesiology and Pain Medicine Nitrogen Protoxide chemistry Additive function Anesthesia Anesthetics Inhalation Animals Medicine business medicine.drug |
| Zdroj: | Canadian Journal of Anaesthesia. 45:466-470 |
| ISSN: | 1496-8975 0832-610X |
| Popis: | To test the hypothesis that the MAC values of nitrous oxide (N2O) and isoflurane were not linearly additive, as theorized by the postulated mode of action based on lipid solubility, in a rat model.Eight Long Evans rats were randomly assigned to order of measurement of MAC for isoflurane and N2O alone and in combination using standard 45 sec supramaximal electrical stimulation (50 volts x 10 msec duration pulses at 50.sec-1 applied for 45 sec s.c. to the lower abdominal groin area). The MAC of N2O was measured at hyperbaric compression to 2.25 atmospheres absolute, 1710 mmHg.The MAC values found were: isoflurane -0.98 +/- 0.12 and N2O - 159 +/- 12 volume (vol)%, or 1.59 +/- 0.12 atmospheres absolute (ATA) (All values are mean +/- standard deviation). The linear additivity theory suggests % MAC agent A + % MAC agent B = 1.0. However, % MAC isoflurane + % MAC N2O = 1.37 +/- 0.15 (P.001).Nonlinear additivity was demonstrated with direct MAC measurement for both isoflurane and N2O in rats. This suggests an agonist-antagonist relationship. |
| Databáze: | OpenAIRE |
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