Biomaterial Database

Drug distribution studies with microdialysis. III: Extracellular concentration of caffeine in adipose tissue in man. 1991

L Ståhle, and P Arner, and U Ungerstedt

Department of Pharmacology, Karolinska Institute, Stockholm, Sweden.

Microdialysis was applied to estimate the extracellular concentration of caffeine in subcutaneous abdominal adipose tissue of five healthy volunteers after oral administration of approximately 5 mg/kg (300 or 400 mg) of caffeine. The peak extracellular levels were in the range of 20 - 80 microM. The time-course in blood and in extracellular fluid was similar but the plateau concentrations were not closely correlated. The estimated mean concentration of five individuals was similar in blood and extracellular fluid. The intraindividual variation between probes was found to be small compared to the interindividual variation (8% versus 43%). It is concluded that microdialysis yield useful data on drug distribution in man and that distribution to adipose tissue may not strictly follow the concentrations in blood. A comparison with available information of the in vitro properties of caffeine shows that the levels attained in the extracellular fluid were too small to significantly affect phosphodiesterase but sufficiently high to block adenosine receptors.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D010726	Phosphodiesterase Inhibitors	Compounds which inhibit or antagonize the biosynthesis or actions of phosphodiesterases.	Phosphodiesterase Antagonists,Phosphodiesterase Inhibitor,Phosphoric Diester Hydrolase Inhibitors,Antiphosphodiesterases,Inhibitor, Phosphodiesterase
D011983	Receptors, Purinergic	Cell surface proteins that bind PURINES with high affinity and trigger intracellular changes which influence the behavior of cells. The best characterized classes of purinergic receptors in mammals are the P1 receptors, which prefer ADENOSINE, and the P2 receptors, which prefer ATP or ADP.	Methyladenine Receptors,Purine Receptors,Purinergic Receptor,Purinergic Receptors,Purinoceptors,Purine Receptor,Purinoceptor,Receptors, Methyladenine,Receptors, Purine,Receptor, Purine,Receptor, Purinergic
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D002110	Caffeine	A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.	1,3,7-Trimethylxanthine,Caffedrine,Coffeinum N,Coffeinum Purrum,Dexitac,Durvitan,No Doz,Percoffedrinol N,Percutaféine,Quick-Pep,Vivarin,Quick Pep,QuickPep
D003956	Dialysis	A process of selective diffusion through a membrane. It is usually used to separate low-molecular-weight solutes which diffuse through the membrane from the colloidal and high-molecular-weight solutes which do not. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Dialyses
D005110	Extracellular Space	Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.	Intercellular Space,Extracellular Spaces,Intercellular Spaces,Space, Extracellular,Space, Intercellular,Spaces, Extracellular,Spaces, Intercellular
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000273	Adipose Tissue	Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.	Fatty Tissue,Body Fat,Fat Pad,Fat Pads,Pad, Fat,Pads, Fat,Tissue, Adipose,Tissue, Fatty