Transglutaminase activity in reversible cerebral ischemia in the rat.
Transglutaminase (TG, EC 2.3.2.13) activity and levels of putrescine (a natural acyl-acceptor in the transglutaminase reaction) were measured in rat brains after 30 min ischemia and 8 or 24 h recirculation. TG activity was significantly increased in the striatum and hippocampus already during cerebral ischemia and, more pronounced, after 8 and 24 h recirculation. In the cortex, in contrast, TG activity did not change during ischemia and 8 h recirculation but was significantly increased after 24 h recirculation. Putrescine levels were sharply increased after 8 h recirculation and even further after 24 h recirculation. It is suggested that in vivo during ischemia and early recirculation, when cells are overloaded with calcium ions, a pathological increase in the TG-catalyzed cross-linking of proteins may be apparent especially in the nerve endings of the hippocampus where the intrinsic concentration of the acyl-donor (protein-bound glutamyl-moiety) has been shown to be high.
Paschen
W
W
Max-Planck-Institute for Neurological Research, Department of Experimental Neurology, Cologne, F.R.G.
Röhn
G
G
Schmidt-Kastner
R
R
D000818:Animals; D002546:Ischemic Attack, Transient / Q000201:enzymology*; D011700:Putrescine / Q000378:metabolism; D051381:Rats; D011503:Transglutaminases / Q000378:metabolism*
D011503:Transglutaminases; D011700:Putrescine