PMID- 18435874 OWN - NLM STAT- MEDLINE DCOM- 20080725 LR - 20181201 IS - 0023-6772 (Print) IS - 0023-6772 (Linking) VI - 42 IP - 2 DP - 2008 Apr TI - Comparative effects of halothane, isoflurane, sevoflurane and desflurane on the electroencephalogram of the rat. PG - 161-70 LID - 10.1258/la.2007.06019e [doi] AB - Inhalant anaesthetic agents are commonly used in studies investigating the electroencephalographic (EEG) effects of noxious stimuli in animals. Halothane causes less EEG depression than isoflurane, however, the EEG effects of halothane, isoflurane, sevoflurane and desflurane have not been compared in the same model. This study aimed to compare the EEG effects of these inhalational agents in the rat. Forty male Sprague-Dawley rats were assigned to four groups and anaesthetized with halothane, isoflurane, sevoflurane or desflurane. EEG was recorded from the left and right somatosensory cortices for 5 min at three different multiples of minimal alveolar concentration (MAC) (1.25, 1.5 and 1.75). Median, 95% spectral edge frequency and total power were derived and a single mean value for each was calculated for the first 60 s of each recording period. When the raw EEG contained burst suppression (BS), the BS ratio (BSR) over 60 s was calculated. No BS was found in EEG recorded from the halothane group at any concentration. BS was present at all concentrations with the other anaesthetic agents. BS was almost complete at all concentrations of isoflurane, whereas BSR increased significantly with increasing concentrations of sevoflurane and desflurane. No significant differences were found between the BSR due to the 1.75 MAC multiple of isoflurane, sevoflurane or desflurane. Halothane causes significantly less depression of cortical activity than the newer inhalant agents at equivalent multiples of MAC. These data support the hypothesis that halothane has a fundamentally different mechanism of action than the other inhalant agents. FAU - Murrell, J C AU - Murrell JC AD - Comparative Anatomy and Physiology, Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand. jo.murrell@bristol.ac.uk FAU - Waters, D AU - Waters D FAU - Johnson, C B AU - Johnson CB LA - eng PT - Comparative Study PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - England TA - Lab Anim JT - Laboratory animals JID - 0112725 RN - 0 (Anesthetics, Inhalation) RN - 0 (Methyl Ethers) RN - 38LVP0K73A (Sevoflurane) RN - CRS35BZ94Q (Desflurane) RN - CYS9AKD70P (Isoflurane) RN - UQT9G45D1P (Halothane) SB - IM MH - Anesthetics, Inhalation/*pharmacology MH - Animals MH - Animals, Laboratory MH - Desflurane MH - Dose-Response Relationship, Drug MH - Electroencephalography/*drug effects/veterinary MH - Halothane/pharmacology MH - Isoflurane/analogs & derivatives/pharmacology MH - Male MH - Methyl Ethers/pharmacology MH - Models, Animal MH - Random Allocation MH - Rats MH - Rats, Sprague-Dawley MH - Sevoflurane EDAT- 2008/04/26 09:00 MHDA- 2008/07/26 09:00 CRDT- 2008/04/26 09:00 PHST- 2008/04/26 09:00 [pubmed] PHST- 2008/07/26 09:00 [medline] PHST- 2008/04/26 09:00 [entrez] AID - 10.1258/la.2007.06019e [doi] PST - ppublish SO - Lab Anim. 2008 Apr;42(2):161-70. doi: 10.1258/la.2007.06019e.