Autoradiographic analysis of second-messenger and neurotransmitter receptor systems in the exo-focal remote areas of postischemic rat brain.
We studied the chronological changes of protein kinase C (PKC) and muscarinic acetylcholine receptor binding activities of the rat brain which were determined by using [3H]phorbol 12,13-dibutyrate (PDBu) and [3H]quinuclidinyl benzilate (QNB) autoradiographic methods, respectively, after 90 min of right middle cerebral artery (MCA) occlusion and after such occlusion, followed by different periods of recirculation. After the ischemic insult followed by 3 h of recirculation, [3H]PDBu binding sites were found to be significantly decreased in the cerebral cortex and lateral segment of the caudate putamen, both supplied by the occluded MCA; thereafter, the binding sites decreased progressively in those ischemic foci. On the contrary, there was no alteration on day 1, but 3 days after ischemic insult, a significant decrease of [3H]QNB binding sites was first detected in those ischemic foci. Moreover, 3 days after ischemic insult, both [3H]PDBu and [3H]QNB binding sites were concurrently reduced in the ipsilateral thalamus and 1 week after the ischemia, in the substantia nigra, in which both areas had not been directly affected by the original ischemic insult. These alterations of PKC in the postischemic brain areas developed concurrently with 45Ca accumulation, which was detected in our previous study. These results suggest that postischemic alterations of second-messenger (PKC) and neurotransmitter receptor systems were involved not only in the ischemic foci due to ischemia-induced energy failure, but also in the exo-focal remote areas prior to the histologic changes where neuronal damage might be caused by transsynaptic delayed degeneration.
Department of Neurology, Institute of Brain Diseases, Tohoku University School of Medicine, Sendai, Japan.
H
H
Nagasawa
T
T
Araki
K
K
Kogure
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D004195:Disease Models, Animal; D002546:Ischemic Attack, Transient / Q000378:metabolism*; D008297:Male; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology*; D013378:Substantia Nigra / Q000378:metabolism; D013788:Thalamus / Q000378:metabolism
D011976:Receptors, Muscarinic; D015240:Phorbol 12,13-Dibutyrate; D011813:Quinuclidinyl Benzilate; D011493:Protein Kinase C