Anesthetic requirement of isoflurane is reduced in spontaneously hypertensive and Wistar-Kyoto rats.

The isoflurane requirement to keep 50% of rats (Rattus norvegicus) unresponsive to noxious stimuli (MAC) was determined in age matched Sprague-Dawley (SD, n = 8), Spontaneously Hypertensive (SHR, n = 8) and Wistar-Kyoto (WKY, n = 8) strains. Following induction and orotracheal intubation, each rat received isoflurane (1.65% end-tidal) for 120 minutes. Physiologic parameters were similar except for expected differences in mean arterial pressure (148 +/- 13mmHg-SHR group, 101 +/- 10mmHg-SD group and 94 +/- 12mmHg-WKY group [mean +/- standard deviation]). Anesthetic equilibration was verified by infrared analysis of end-tidal gases. MAC was then determined in each rat by the tail clamp method and a group MAC calculated.