Biomaterial Database

Effects of anesthetic and nonanesthetic steroids on dipalmitoylphosphatidylcholine liposomes: a calorimetric and Raman spectroscopic investigation. 1984

T J O'Leary, and P D Ross, and I W Levin

The effects of anesthetic and nonanesthetic steroids on dipalmitoylphosphatidylcholine liposomes were studied by use of high sensitivity scanning calorimetry and Raman spectroscopy. Calorimetric measurements indicated that both anesthetic and nonanesthetic steroids depressed and broadened the gel to liquid-crystalline phase transition. There was no correlation between the perturbations by the steroids on the primary gel to liquid-crystalline phase transition temperature and anesthetic potency. The magnitudes of the steroid-induced transition broadening and lowering of the pretransition temperature, however, correlated well with anesthetic potency. This effect appeared to arise from the projection from the plane of the D ring of substituents at the C(17) position of the steroid nucleus. Raman spectroscopic measurements demonstrated that the steroid molecule is localized within the acyl region of the bilayer and that effects of the steroid do not extend to either the head-group or interface regions of the lamellae. The data are consistent with unitary hypotheses relating general anesthesia to lipid perturbations. For model systems, perturbations to the subtle structural and dynamical properties of the bilayer pretransition may provide a more sensitive marker than the main phase transition in assessing the significance of lipid mediation in inducing anesthetic action.

UI	MeSH Term	Description	Entries
D008081	Liposomes	Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.	Niosomes,Transferosomes,Ultradeformable Liposomes,Liposomes, Ultra-deformable,Liposome,Liposome, Ultra-deformable,Liposome, Ultradeformable,Liposomes, Ultra deformable,Liposomes, Ultradeformable,Niosome,Transferosome,Ultra-deformable Liposome,Ultra-deformable Liposomes,Ultradeformable Liposome
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D011277	Pregnanediones	Pregnane derivatives in which two side-chain methyl groups or two methylene groups in the ring skeleton (or a combination thereof) have been oxidized to keto groups.	Diketopregnanes,Dioxopregnanes
D011663	Pulmonary Surfactants	Substances and drugs that lower the SURFACE TENSION of the mucoid layer lining the PULMONARY ALVEOLI.	Surfactants, Pulmonary,Pulmonary Surfactant,Surfactant, Pulmonary
D002152	Calorimetry, Differential Scanning	Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.	Differential Thermal Analysis, Calorimetric,Calorimetric Differential Thermal Analysis,Differential Scanning Calorimetry,Scanning Calorimetry, Differential
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
D013059	Spectrum Analysis, Raman	Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.	Raman Spectroscopy,Analysis, Raman Spectrum,Raman Optical Activity Spectroscopy,Raman Scattering,Raman Spectrum Analysis,Scattering, Raman,Spectroscopy, Raman
D013256	Steroids	A group of polycyclic compounds closely related biochemically to TERPENES. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (STEROLS), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. (From Hawley's Condensed Chemical Dictionary, 11th ed)	Steroid,Catatoxic Steroids,Steroids, Catatoxic
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships