Publication Date:
1992-12-11
Description:
The range of messenger action of a point source of Ca2+ or inositol 1,4,5-trisphosphate (IP3) was determined from measurements of their diffusion coefficients in a cytosolic extract from Xenopus laevis oocytes. The diffusion coefficient (D) of [3H]IP3 injected into an extract was 283 microns 2/s. D for Ca2+ increased from 13 to 65 microns 2/s when the free calcium concentration was raised from about 90 nM to 1 microM. The slow diffusion of Ca2+ in the physiologic concentration range results from its binding to slowly mobile or immobile buffers. The calculated effective ranges of free Ca2+ before it is buffered, buffered Ca2+, and IP3 determined from their diffusion coefficients and lifetimes were 0.1 micron, 5 microns, and 24 microns, respectively. Thus, for a transient point source of messenger in cells smaller than 20 microns, IP3 is a global messenger, whereas Ca2+ acts in restricted domains.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Allbritton, N L -- Meyer, T -- Stryer, L -- 5F32AI0814203/AI/NIAID NIH HHS/ -- MH45324/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1992 Dec 11;258(5089):1812-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Stanford University, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1465619" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Calcium/*metabolism
;
Calcium-Transporting ATPases/antagonists & inhibitors
;
Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone/pharmacology
;
Chromatography, High Pressure Liquid
;
Cytosol/metabolism
;
Diffusion
;
Inositol 1,4,5-Trisphosphate/*metabolism
;
Kinetics
;
Oocytes/drug effects/*metabolism
;
*Second Messenger Systems
;
*Signal Transduction
;
Terpenes/pharmacology
;
Thapsigargin
;
Time Factors
;
Xenopus laevis
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
