Biomaterial Database

General anesthetics inhibit cytochrome P450 monooxygenases and arachidonic acid metabolism. 1993

F S LaBella, and G Queen

Department of Pharmacology and Therapeutics, University of Manitoba, Faculty of Medicine, Winnipeg, Man., Canada.

Identification of a specific biomolecular target appropriately sensitive to a wide array of anesthetics has been elusive. At concentrations close to their respective ED50's for anesthesia in man or other species, 18 compounds, differing in potencies up to 66,000 fold, inhibited cytochrome P450 mediated metabolism of aminopyrine, a synthetic substrate, and arachidonic acid (AA), an endogenous substrate, in isolated liver microsomes. There was a highly significant correlation for both substrates between the absolute concentrations required for anesthesia (EC50) and for inhibition of P450 activity (Ki or IC50). The mean Ki/EC50 ratio was 0.97 for inhibition of aminopyrine demethylase. The mean IC50/EC50 ratios were 0.42 and 0.64 for inhibition of two AA-derived products and 2.8 for a third; a mean ratio of 1.4 for inhibition of overall AA metabolism suggests interaction of general anesthetics with a composite of P450 isozymes. The universal cytochrome P450 monooxygenases, in conjunction with other lipid oxygenases (cyclooxygenases and lipoxygenases) participate in the second messenger AA cascade. In nerve cells the sensitivity of these enzymes to hydrophobic neurodepressant drugs may underlie the state of general anesthesia: reversible disruption of intracellular and intercellular signalling without impairment of enzymes vital to cell respiration.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D006899	Mixed Function Oxygenases	Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.	Hydroxylase,Hydroxylases,Mixed Function Oxidase,Mixed Function Oxygenase,Monooxygenase,Monooxygenases,Mixed Function Oxidases,Function Oxidase, Mixed,Function Oxygenase, Mixed,Oxidase, Mixed Function,Oxidases, Mixed Function,Oxygenase, Mixed Function,Oxygenases, Mixed Function
D000633	Aminopyrine N-Demethylase		Aminopyrine N Demethylase,Demethylase, Aminopyrine N,N Demethylase, Aminopyrine,N-Demethylase, Aminopyrine
D000777	Anesthetics	Agents capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general ANESTHESIA, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.	Anesthetic,Anesthetic Agents,Anesthetic Drugs,Anesthetic Effect,Anesthetic Effects,Agents, Anesthetic,Drugs, Anesthetic,Effect, Anesthetic,Effects, Anesthetic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D016718	Arachidonic Acid	An unsaturated, essential fatty acid. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is formed by the synthesis from dietary linoleic acid and is a precursor in the biosynthesis of prostaglandins, thromboxanes, and leukotrienes.	(all-Z)-5,8,11,14-Eicosatetraenoic acid,Arachidonic Acid, (all-Z)-Isomer, 1-(14)C-Labeled,Arachidonic Acid, (all-Z)-isomer, 3H-Labeled,Arachidonic Acid, Ammonium Salt, (all-Z)-Isomer,Arachidonic Acid, Cerium Salt, (all-Z)-Isomer,Arachidonic Acid, Cesium Salt, (all-Z)-Isomer,Arachidonic Acid, Lithium Salt, (all-Z)-Isomer,Arachidonic Acid, Potassium Salt, (all-Z)-Isomer,Arachidonic Acid, Sodium Salt,Arachidonic Acid, Sodium Salt, (all-Z)-Isomer,Arachidonic Acid, Zinc Salt, (all-Z)-Isomer,Sodium Arachidonate,Vitamin F,Arachidonate, Sodium
D017207	Rats, Sprague-Dawley	A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.	Holtzman Rat,Rats, Holtzman,Sprague-Dawley Rat,Rats, Sprague Dawley,Holtzman Rats,Rat, Holtzman,Rat, Sprague-Dawley,Sprague Dawley Rat,Sprague Dawley Rats,Sprague-Dawley Rats
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus
D065607	Cytochrome P-450 Enzyme Inhibitors	Drugs and compounds which inhibit or antagonize the biosynthesis or actions of CYTOCHROME P-450 ENZYMES.	Cytochrome P-450 Inhibitors,Cytochrome P-450 Monooxygenase Inhibitors,Cytochrome P-450 Oxygenase Inhibitors,Cytochrome P-450-Dependent Monooxygenase Inhibitors,P-450 Enzyme Inhibitors,P450 Enzyme Inhibitors,Cytochrome P 450 Dependent Monooxygenase Inhibitors,Cytochrome P 450 Enzyme Inhibitors,Cytochrome P 450 Inhibitors,Cytochrome P 450 Monooxygenase Inhibitors,Cytochrome P 450 Oxygenase Inhibitors,Enzyme Inhibitors, P-450,Enzyme Inhibitors, P450,Inhibitors, Cytochrome P-450,Inhibitors, P-450 Enzyme,Inhibitors, P450 Enzyme,P 450 Enzyme Inhibitors,P-450 Inhibitors, Cytochrome