Effect of incomplete ischemia and reperfusion of the rat brain on the density and affinity of alpha-adrenergic binding sites in the cerebral cortex. Prevention of changes by stobadine and vitamin E.
The effect of incomplete 4 hr ischemia and subsequent 1 hr reperfusion of the rat brain on the density and affinity of alpha-adrenergic binding sites was investigated. To assess the involvement of oxygen-derived free radicals in the development of ischemic injury, we tested the effect of stobadine and vitamin E on putative changes of the binding parameters of alpha-adrenergic binding sites in ischemic and reperfused rat brains. Compared to the group of sham operated animals decreased density and increased affinity of [3H]dihydroergocryptine binding sites was found in cerebrocortical membranes of rats subjected to 4 hr incomplete ischemia and 1 hr reperfusion. The reduction of Bmax and Kd induced by ischemia and reperfusion of the brain was prevented by stobadine and vitamin E administration. Neither incomplete ischemia nor incomplete ischemia and subsequent reperfusion of the rat brain exerted significant effect on [3H]rauwolscine binding to alpha 2-adrenergic binding sites. Our results suggest that brain ischemia and reperfusion may affect the density and affinity of alpha 1- rather than of alpha 2-adrenergic binding sites. The beneficial effect of stobadine and vitamin E indicates that increased generation of oxygen free radicals might play a role in the development of these changes.
Kvaltínová
Z
Z
Institute of Experimental Pharmacology, Slovak Academy of Sciences, Bratislava.
Lukovic
L
L
Stolc
S
S
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002545:Brain Ischemia / Q000378:metabolism*; D002243:Carbolines / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004088:Dihydroergotoxine / Q000493:pharmacokinetics; D005609:Free Radicals; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000378:metabolism; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects / Q000378:metabolism; D015424:Reperfusion; D014810:Vitamin E / Q000494:pharmacology*; D015016:Yohimbine / Q000493:pharmacokinetics
D000975:Antioxidants; D002243:Carbolines; D005609:Free Radicals; D017382:Reactive Oxygen Species; D011942:Receptors, Adrenergic, alpha; D018340:Receptors, Adrenergic, alpha-1; D018341:Receptors, Adrenergic, alpha-2; D004088:Dihydroergotoxine; D014810:Vitamin E; D015016:Yohimbine; C100106:dicarbine