Acute depression of energy metabolism after microdialysis probe implantation is distinct from ischemia-induced changes in mouse brain.
The current study used measurements of metabolites and markers of membrane integrity to determine the most suitable time point for microdialysis experiments following probe implantation. Leakage of Evans blue and sodium fluorescein indicated increased BBB permeability only immediately (15 min), but not 1.5 and 24 h following probe implantation. Acute implantation decreased glucose and lactate levels relative to the levels after 24 h (to 13-37% and 25-60%, respectively). No change in extracellular levels of glutamate or glycerol was seen. In comparison to acute probe implantation, the pattern of damage under brain ischemia (middle cerebral artery occlusion) differed: While glucose levels dropped, lactate levels rose after ischemia, and glutamate (tenfold) and glycerol (eightfold) increased sharply. In conclusion, acute implantation of a microdialysis probe causes transient depression of the energy metabolites, glucose and lactate, likely due to injury-induced hypermetabolism. However, no massive tissue damage or severe ischemic conditions around the probe occur.
Sumbria
Rachita K
RK
Department of Pharmaceutical Sciences and Center for Vascular Drug Research, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 Coulter Dr, Amarillo, TX 79106, USA.
Klein
Jochen
J
Bickel
Ulrich
U
D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology; D002545:Brain Ischemia / Q000378:metabolism*; D004734:Energy Metabolism; D005947:Glucose / Q000134:cerebrospinal fluid; D005971:Glutamates / Q000134:cerebrospinal fluid; D005990:Glycerol / Q000134:cerebrospinal fluid; D020244:Infarction, Middle Cerebral Artery; D019344:Lactic Acid / Q000134:cerebrospinal fluid; D008297:Male; D051379:Mice; D017551:Microdialysis / Q000295:instrumentation* / Q000379:methods
D005971:Glutamates; D019344:Lactic Acid; D005947:Glucose; D005990:Glycerol