FE-56 IRRADIATION DIMINISHES MUSCARINIC BUT NOT ALPHA(1)-ADRENERGIC-STIMULATED LOW-K-M GTPASE IN RAT-BRAIN

Citation
R. Villalobosmolina et al., FE-56 IRRADIATION DIMINISHES MUSCARINIC BUT NOT ALPHA(1)-ADRENERGIC-STIMULATED LOW-K-M GTPASE IN RAT-BRAIN, Radiation research, 140(3), 1994, pp. 382-386
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Radiology,Nuclear Medicine & Medical Imaging
Journal title
ISSN journal
0033-7587
Volume
140
Issue
3
Year of publication
1994
Pages
382 - 386
Database
ISI
SICI code
0033-7587(1994)140:3<382:FIDMBN>2.0.ZU;2-L
Abstract
Initial findings from our laboratory have indicated that muscarinic en hancement of K+-evoked release of dopamine from perifused striatal sli ces is reduced after exposure to Fe-56-particle irradiation. This find ing suggested that there is a radiation-induced deficit in muscarinic receptor sensitivity. Subsequent findings have indicated that at least part of the loss in sensitivity may occur as a result of alterations in the initial steps of the signal transduction process and involve mu scarinic receptor-G protein coupling/uncoupling. The present study was carried out to localize this deficit further by determining carbachol -stimulated low-Km guanosine triphosphatase (GTPase) activity in stria tal and hippocampal tissue obtained from rats exposed to 0, 0.1 or 1.0 Gy of Fe-56-particle irradiation. In addition, to examine the specifi city of the effect of Fe-56-particle irradiation, alpha(1)-adrenergic- stimulated low-K-m GTPase activity was also examined in these tissues. The results showed that there was a high degree of specificity in the effects of Fe-56 particles. Decrements were observed in muscarinic-st imulated low-K-m GTPase in striatum but not in hippocampus, and Fe-56- particle irradiation did not affect alpha(1)-adrenergic low-K-m GTPase activity in either brain tissue.