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Brain somatostatin receptors in a rat model of acute liver failure
Author(s) -
BoyanoAdánez Maria Del Carmen,
Barrios Vicente,
Afulla Eduardo
Publication year - 1995
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890200208
Subject(s) - medicine , somatostatin , endocrinology , hippocampus , somatostatin receptor , receptor , galactosamine , cortex (anatomy) , chemistry , biology , biochemistry , neuroscience , glucosamine
The present study examines the effect of acute liver failure induced by a single intraperitoneal (i.p.) injection of D‐galactosamine‐HC1(3 gkg) on somatostatin (SS) binding and levels in the rat frontoparietal cortex and hippocampus. Neurobehavioural changes were evaluated by the method of Zieve et al. (1984)J. Lab. Clin. Med., 1046554641.The rats were decapitated as soon as they reached neurobehavioural stage I or 11. In stage I, rats had lethargy and in stage I1 they showed mild ataxia, mainly in the hind limbs. The administration of D‐galactosamine elevated serum transaminase levels (mean peak level 2,242 IU/1) but hypoglycemia, gross cerebral edema, or signs of sepsis were not detected in any of the animals studied. In addition, D‐galactosamine did not affect somatostatin‐like immunoreactivity (SSLI) levels in either brain area in any of the experimental groups as compared to the control groups. The rats sacrificed in stage I showed no change in the number or affinity of specific 125 I‐Tyr 11 ‐somatostatin( 125 I‐Tyr 11 ‐SS)receptors in synaptosomes from the frontoparietal cortex and hippocampus. The rats sacrificed in stage II showed a decrease in the number of specific 125 I‐Tyr 11 ‐SS receptors in synaptosomes from both brain areas, with no change in receptor affinity. Binding studies were also conducted on synaptosomes from the frontoparietal cortex and hippocampus of rats that received D‐galactosamine but did not develop acute liver failure and consequently did not develop neurobehavioural changes. The SS receptors in these synaptosomes did not change in comparison with controls, indicating that the D‐galactosamine was not directly responsible for the changes in the cerebral SS receptors. SS caused a significantly lower inhibition in AC activity in frontoparietal cortex and hippocampal membranes of D‐galactosamine‐treated rats sacrificed in stage II. No significant differences were seen for the basal or for the forskolin (FK)‐stimulated AC activities in all groups. The results of this study indicate that D‐galactosamine‐induced acute liver failure in rats is associated with a decrease of the number of SS receptors and the inhibitory effect of SS on adenylyl cyclase (AC) activity in frontoparietal cortex and hippocampus when the animals showed neurobehavioural stage II from Zieve et al. [(1984)J. Lab. Clin. Med., 104:655‐664]. © 1995 Wiley‐Liss, Inc.